Section 48. As used in sections 49 to 55, inclusive, the following words shall, unless the context requires otherwise, have the following meanings:—

''Alimony'', the payment of support from a spouse, who has the ability to pay, to a spouse in need of support for a reasonable length of time, under a court order.

''Full retirement age'', the payor's normal retirement age to be eligible to receive full retirement benefits under the United States Old Age, Survivors, and Disability Insurance program; but shall not mean ''early retirement age,'' as defined under 42 U.S.C. 416, if early retirement is available to the payor or maximum benefit age if additional benefits are available as a result of delayed retirement.

''General term alimony'', the periodic payment of support to a recipient spouse who is economically dependent.

''Length of the marriage'', the number of months from the date of legal marriage to the date of service of a complaint or petition for divorce or separate support duly filed in a court of the commonwealth or another court with jurisdiction to terminate the marriage; provided, however, that the court may increase the length of the marriage if there is evidence that the parties' economic marital partnership began during their cohabitation period prior to the marriage.

''Rehabilitative alimony'', the periodic payment of support to a recipient spouse who is expected to become economically self-sufficient by a predicted time, such as, without limitation, reemployment; completion of job training; or receipt of a sum due from the payor spouse under a judgment.

''Reimbursement alimony'', the periodic or one-time payment of support to a recipient spouse after a marriage of not more than 5 years to compensate the recipient spouse for economic or noneconomic contribution to the financial resources of the payor spouse, such as enabling the payor spouse to complete an education or job training.

''Transitional alimony'', the periodic or one-time payment of support to a recipient spouse after a marriage of not more than 5 years to transition the recipient spouse to an adjusted lifestyle or location as a result of the divorce.