§ 1320. Definitions. The following words and phrases as used in this article shall have the following meanings unless a different meaning is plainly required by the context:

a. "Retirement system" shall mean the New York city employees' retirement system, the New York city teachers' retirement system, and the New York city board of education retirement system.

b. "Eligible employee", subject to the limitations of section thirteen hundred twenty-two of this article, shall mean a member of a retirement system who first became a member of such system on or after April first, two thousand twelve who is identified as eligible to receive the benefit enhancements provided for in this article upon election by the city of New York pursuant to section thirteen hundred twenty-one of this article.