delivered the opinion of the court:
Donnie Robbins petitioned the Carbondale Police Pension Fund for a disability pension pursuant to article III of the Illinois Pension Code. 40 ILCS 5/3 — 101 et seq. (West 1992). The fund’s board of trustees (Board) denied Robbins a line-of-duty disability pension, but granted him a nonduty disability pension.
On administrative review, the circuit court of Jackson County confirmed the Board’s decision. However, the appellate court reversed and entered judgment in favor of Robbins for a line-of-duty disability pension. 283 Ill. App. 3d 823. We allowed the Board’s petition for leave to appeal (155 Ill. 2d R. 315(a)) and now reverse the appellate court.
BACKGROUND
The appellate court detailed the evidence in this case. 283 Ill. App. 3d at 824-26. Therefore, we will repeat only those facts necessary for our disposition of this appeal. Briefly, in 1970, Robbins began working for the Carbondale police department. From 1970 to 1979, he worked as a patrol officer. From 1979 to 1988, he worked as an evidence custodian. In 1988, at age 42, Robbins was reassigned to patrol duty.
After his reassignment to patrol duty, Robbins’ performance caused him stress. The several stressful aspects of Robbins’ job generally stemmed from: (1) his supervisor’s criticism of the timeliness and quality of his reports, and (2) his anxiety that his fellow patrol officers were younger and better trained. The record also contains evidence that, on January 1, 1990, Robbins was particularly stressed while responding to a domestic violence call. During that incident, Robbins witnessed a man commit suicide by shooting himself in the face with a shotgun.
Robbins continued working patrol duty until April *5371992, when he injured his hand. In October 1992, he returned to patrol duty. Two weeks later, the Carbon-dale chief of police put Robbins on administrative leave pending a psychological examination. Dr. Eric Ostrov opined that Robbins was not mentally fit for duty. At the end of November 1992, the police chief suspended Robbins from duty.
In December 1992, Robbins petitioned the Carbon-dale Police Pension Fund for a nonduty disability pension, which amounted to 50% of the salary attached to his rank on the force on the date of his suspension. See 40 ILCS 5/3 — 114.2 (West 1992). In January 1994, Robbins amended his petition to add a claim for a line-of-duty disability pension, which amounted to 65% of the salary attached to his rank on the date of his suspension. See 40 ILCS 5/3 — 114.1 (West 1992).
In March 1994, Robbins testified before the Board and submitted three psychological evaluations. The Board subsequently received the evidence deposition of Dr. Ostrov. On September 22, 1994, the Board denied Robbins a line-of-duty disability pension, but granted him a nonduty disability pension.
Robbins filed a complaint in the circuit court of Jackson County seeking administrative review of the Board’s denial of a line-of-duty pension. The circuit court confirmed the Board’s decision. However, the appellate court reversed the circuit court and the Board. The appellate court entered judgment in favor of Robbins for a line-of-duty disability pension. The Board appeals.
DISCUSSION
We explain at the outset our standard of review. Article III of the Pension Code provides that judicial review of the Board’s decisions be in accordance with the Administrative Review Law (735 ILCS 5/3 — 101 et seq. (West 1994)). 40 ILCS 5/3 — 148 (West 1994). The Administrative Review Law provides that our review *538extends to all questions of law and fact presented by the entire record. The statute limits our review to the record before us; we may not hear new or additional evidence. The statute also mandates that the "findings and conclusions of the administrative agency on questions of fact shall be held to be prima facie true and correct.” 735 ILCS 5/3 — 110 (West 1994).
On administrative review, a court’s function is to ascertain whether the findings and decision of the agency are against the manifest weight of the evidence. An administrative agency decision is against the manifest weight of the evidence only if the opposite conclusion is clearly evident. The mere fact that an opposite conclusion is reasonable or that the reviewing court might have ruled differently will not justify reversal of the administrative findings. If the record contains evidence that supports the agency’s decision, it should be upheld. Abrahamson v. Illinois Department of Professional Regulation, 153 Ill. 2d 76, 88 (1992).
In this case, the appellate court stated that it was not deciding whether the Board’s decision was against the manifest weight of the evidence, but rather, whether the Board and the circuit court properly applied the law to the facts. 283 Ill. App. 3d at 827. The rule that an administrative agency’s findings of fact should not be disturbed unless they are against the manifest weight of the evidence does not apply where the question involved is one of law, such as the proper interpretation of a statute. Rather, in such a case, the Board’s finding is not binding on the court. Envirite Corp. v. Illinois Environmental Protection Agency, 158 Ill. 2d 210, 214 (1994); DiFoggio v. Retirement Board of the County Employees Annuity & Benefit Fund, 156 Ill. 2d 377, 380-81 (1993).
Section 3 — 114.1 of the Pension Code provides for a line-of-duty disability pension as follows:
"Disability pension — Line of Duty. If a police officer as the result of sickness, accident or injury incurred in or *539resulting from the performance of an act of duty, is found to be physically or mentally disabled for service in the police department, so as to render necessary his or her suspension or retirement from the police service, the police officer shall be entitled to a disability retirement pension of 65% of the salary attached to the rank on the police force held by the officer at the date of suspension of duty or retirement. A police officer shall be considered 'on duty’, while on any assignment approved by the chief of the police department of the municipality he or she serves, whether the assignment is within or outside the municipality.” 40 ILCS 5/3 — 114.1 (West 1994).
In contrast, Pension Code section 3 — 114.2 provides for a nonduty pension. Under this section, a nonduty pension shall be granted to "a police officer who becomes disabled as a result of any cause other than the performance of an act of duty, and who is found to be physically or mentally disabled so as to render necessary his or her suspension or retirement from police service in the police department.” A nonduty disability pension amounts to "50% of the salary attached to the officer’s rank on the police force at the date of suspension of duty or retirement.” 40 ILCS 5/3 — 114.2 (West 1994). The controlling principles are familiar:
"The primary rule of statutory interpretation is that a court should ascertain and give effect to the intention of the legislature. The legislative intent should be sought primarily from the language used in the statute. [Citation.] The statute should be evaluated as a whole; each provision should be construed in connection with every other section. [Citation.] 'Where the language of the act is certain and unambiguous the only legitimate function of the courts is to enforce the law as enacted by the legislature.’ [Citation.]” Abrahamson, 153 Ill. 2d at 91.
"An Act of Duty”
Pension Code section 3 — 114.1 requires, inter alla, that the officer’s disability result from "an act of duty.” 40 ILCS 5/3 — 114.1 (West 1994). That phrase is not *540defined in that section or anywhere in article III of the Pension Code. However, that phrase is defined in article V of the Code. 40 ILCS 5/5 — 113 (West 1994). Article III of the Code pertains to police pension funds in municipalities with populations under 500,000, while article V pertains to the same subject in municipalities with populations exceeding 500,000. Compare 40 ILCS 5/3— 101 et seq. (West 1994) with 40 ILCS 5/5 — 101 et seq. (West 1994).
We may look to article V of the Pension Code for a definition of language used in article III of the Code. We emphasize that:
"the intent of the legislature in enacting a statute must be determined by examining the entire statute and by construing each material part of the legislation together. [Citation.] A court should consider each part or section of a legislative act in connection with every other part or section, and not each part alone, in determining the purpose or intent of the legislature.” (Emphasis in original.) Castaneda v. Illinois Human Rights Comm’n, 132 Ill. 2d 304, 318 (1989).
Accord Huckaba v. Cox, 14 Ill. 2d 126, 131 (1958). "Moreover, when an act defines its terms, those terms must be construed according to the definitions contained in the act.” People ex rel. Scott v. Schwulst Building Center, Inc., 89 Ill. 2d 365, 371 (1982); accord Garza v. Navistar International Transportation Corp., 172 Ill. 2d 373, 379 (1996).
We note that the appellate court has specifically used Pension Code section 5 — 113 as a guide to interpret the phrase "act of duty” in section 3 — 114.1. Trettenero v. Police Pension Fund, 268 Ill. App. 3d 58, 64-65 (1994); Olson v. City of Wheaton Police Pension Board, 153 Ill. App. 3d 595, 598-99 (1987). However, in Worth v. Board of Trustees of the Police Pension Fund, 230 Ill. App. 3d 349, 354-55 (1992), the appellate court criticized this analysis. The court in Worth relied on Pension Code section 5 — 102, which provides that the terms used in *541article V shall have the meaning ascribed to them by the definitional sections in article V. 40 ILCS 5/5 — 102 (West 1994). Based on this section, the Worth court reasoned that the definition of an "act of duty” in article V of the Code applied only to cases brought under article V. Thus, the Worth court concluded that the definition of "act of duty” in article V of the Code could not be used in a case arising under article III.
We disagree with this reasoning in Worth. Initially, just because the legislature provided that a phrase used in article V, e.g., "act of duty,” is to have the meaning ascribed to it in that article does not mean that the legislature intended the identical phrase in article III to have a different meaning. It is fundamental that where a word or phrase is used in different sections of the same legislative act, a court presumes that the word or phrase is used with the same meaning throughout the act, unless a contrary legislative intent is clearly expressed. Schwulst Building Center, 89 Ill. 2d at 372; Moran v. Katsinas, 16 111. 2d 169, 174 (1959). Based on this principle, this court has approved the use of definitions of phrases in article V of the Pension Code in cases arising under article III. Borg v. Village of Schiller Park Police Pension Board, 99 Ill. 2d 376, 381 (1984).
Moreover, the legislature expressly provided that article, division, or section headings in the Pension Code do not "govern, limit, modify or in any manner affect the scope, meaning or intent of the provisions of any Article, Division or Section hereof.” 40 ILCS 5/1 — 103 (West 1994). The reasoning in Worth on this point is erroneous and is not to be followed.
Pension Code section 5 — 113 defines an "act of duty” as follows:
"Act of Duty. 'Act of duty’: Any act of police duty inherently involving special risk, not ordinarily assumed by a citizen in the ordinary walks of life, imposed on a policeman by the statutes of this State or by the ordinances or *542police regulations of the city in which this Article is in effect or by a special assignment; or any act of heroism performed in the city having for its direct purpose the saving of the life or property of a person other than the policeman.” 40 ILCS 5/5 — 113 (West 1994).'
We agree with the following principles that have developed in applying Pension Code section 3 — 114.1, read together with section 5 — 113, to claims of duty-related stress:
"In examining claims of duty-related stress like the one made in the instant case, courts have required that plaintiff-police officers demonstrate their disabilities are the result of a specific, identifiable act of duty unique to police work. (Ryndak v. River Grove Police Pension Board (1993), 248 Ill. App. 3d 486, 490; Wall v. Police Pension Board (1988), 178 Ill. App. 3d 438, 444; Olson v. City of Wheaton Police Pension Board (1987), 153 Ill. App. 3d 595 (cited with approval in Ryndak and Wall).) Conversely, where the disability is traceable only to the 'general nature of being a police officer’ and not to a specific act of police service, line-of-duty disability pensions are denied. (See Ryndak, 248 Ill. App. 3d at 490.) Similarly, where the causes of the stress are not unique to police work, line-of-duty disability pensions are also denied. (See Wall, 178 Ill. App. 3d at 444; Ryndak, 248 Ill. App. 3d at 490.) These general rules are an outgrowth of judicial attempts to define and apply the term 'act of duty’ to cases involving claimed psychological disabilities.” Trettenero, 268 Ill. App. 3d at 63-64.
Courts reason that civilians regularly suffer stress in many aspects of their jobs. Thus, to be eligible for a line-of-duty disability pension based on stress, a police officer’s psychological disability must result from "a 'special risk, not ordinarily assumed by a citizen in the ordinary walks of life.’ ” Olson, 153 Ill. App. 3d at 599, quoting Ill. Rev. Stat. 1985, ch. 1081/2, par. 5 — 113, now codified at 40 ILCS 5/5 — 113 (West 1994); accord Batka v. Board of Trustees of the Village of Orland Park Police Pension Fund, 186 Ill. App. 3d 715, 724 (1989).
*543In reversing the circuit court and the Board in this case, the appellate court did not address these principles. The appellate court began its reasoning with the phrase from section 3 — 114.1: "incurred in or resulting from the performance of an act of duty.” 40 ILCS 5/3 — 114.1 (West 1994). The court reasoned that the words "incur” and "resulting from” were equivalent to the word "cause.” The court then reasoned that the tort concept of proximate cause allows for more than one cause of an injury. Thus, the court concluded that a disabled police officer should not be deprived of a line-of-duty disability pension as long as one of the causes of the disability resulted from an act of duty. 283 Ill. App. 3d at 827-28. The appellate court entered judgment in favor of Robbins for a line-of-duty disability pension because "Robbins’ debilitating mental condition was caused, at least in part, by his on-duty functions as a police officer.” 283 111. App. 3d at 829.
This circuitous reasoning and its conclusion are erroneous. The appellate court awarded Robbins a line-of-duty disability pension based on generalized police stress of multiple origins that caused his disability. The court based this conclusion on the common law concepts of negligence and proximate cause, and not on the plain language of the Pension Code. "However, a court should not attempt to read a statute other than in the manner in which it was written. In applying plain and unambiguous language, it is not necessary for a court to search for any subtle or not readily apparent intention of the legislature.” DiFoggio, 156 Ill. 2d at 383; see Laborer’s International Union of North America, Local 1280 v. Illinois State Labor Relations Board, 154 Ill. App. 3d 1045, 1057-60 (1987).
As the Board notes, this is a statutory action with explicit requirements and not a common law negligence action. The appellate court had to look no further than *544the plain language of the Pension Code, which requires that the line-of-duty disability result from an act of duty.
The Present Case
It is undisputed that Robbins suffered from stress, which in turn led to, inter alla, depression and alcohol abuse. What is disputed is the source of the stress. In his brief before this court, Robbins claims that his mental disability "resulted from an act of duty and was not a result of generalized stress.” He argues that the report of the Board’s psychologist, Dr. Ostrov, and the reports of his three psychologists, Drs. David Gilliam, James Peterson, and Michael Althoff, all "indicate conclusively” that his disability resulted from witnessing the January 1, 1990, shotgun suicide.
Robbins misreads the record. The Board’s psychologist, Dr. Ostrov, concluded that while Robbins’ stress was related to his police work, the stress was not connected to any specific act of Robbins as a police officer. The conclusions of Robbins’ own three psychologists accord with that of Dr. Ostrov. Drs. Althoff and Peterson each concluded that Robbins had significant daily stress beginning with his reassignment to patrol duty in 1988. Dr. Gilliam specifically concluded: "1. Mr. Robbins’ past exposure to occasional violence was not problematic for him. 2. His continuous exposure to possible violence, as well as the pace of his duties in general, were of considerable stress.” (Emphasis added.) The Board found that this record contained insufficient evidence that the stress resulted from the performance of an act of duty.
We cannot say that the Board’s decision was against the manifest weight of the evidence. Rather, this record contains ample evidence that Robbins’ stress was the result of his anxiety over his job performance, which civilians regularly suffer, and not the performance of a specific act of duty. See, e.g., Trettenero, 268 Ill. App. 3d at 68-69 (and cases cited therein).
*545This is not a case where a police officer’s injury resulted from the performance of a specific act of duty. See, e.g., Johnson v. Retirement Board of the Policemen’s Annuity & Benefit Fund, 114 Ill. 2d 518 (1986). Also, our decision here does not mean that a police officer can never receive a line-of-duty disability pension for a psychological disability. Of course, Robbins still receives a nonduty disability pension. See 40 ILCS 5/3 — 114.2 (West 1994).
CONCLUSION
Courts liberally construe pension laws in favor of those to be benefitted. Colton v. Board of Trustees of the Firemen’s Pension Fund, 287 Ill. 56, 61 (1919); Hahn v. Police Pension Fund, 138 Ill. App. 3d 206, 211 (1985). However:
"[w]hile a pension act should be liberally construed to effect the object sought to be accomplished, yet if the legislative intention is obvious from the language used that intention must be made effective, and the judiciary will not be warranted in giving the act a meaning not expressed in it.” Sup v. Cervenka, 331 Ill. 459, 463 (1928).
For the foregoing reasons, the judgment of the appellate court is reversed, and the judgment of the circuit court of Jackson County is affirmed.
Appellate court reversed; circuit court affirmed.