Okla. Admin. Code § 715:10-17-1
The following words or terms, when used in this subchapter, shall have the following meaning, unless the context clearly indicates otherwise:
"Public school" means all schools, colleges, universities, state agencies, boards, commissions or other state educational entities conducted within the state supported wholly or partly by public funds and operating for any function of public education. All employment by any state agency, which would cause or allow the member to be enrolled in TRS as an active employee will constitute employment by a public school for the purposes of this section. Members receiving service retirement benefits may be employed in private schools, public schools in other states, and in private business without affecting their benefits.
"Retired Member" shall be inclusive of any person, who is receiving monthly benefits from the Teachers' Retirement System of Oklahoma, whether that person is an individual, incorporated entity, corporation, proprietorship, partnership, limited liability company or partnership, or any other business structure that contracts with a public school to perform duties ordinarily performed by classified or non-classified personnel.
"Retirement" means withdrawal from active service, with a retirement benefit in lieu thereof.
Okla. Admin. Code § 715:10-17-1