gap year; sabbatical year

plural of disability-adjusted life year

(medicine) A measure of overall disease burden, expressed as the number of years lost due to ill-health, disability or early death.

Synonym of man-year

plural of person-year

A project that is culmination of an academic course or major. This is typically done at the end of said course or major.

(Ireland, sarcastic) I will not.

plural of terawatt-year

(electricity) A unit of electrical energy equal to that done by one terawatt acting for one year.

(slang) Used to express enthusiastic or gung-ho agreement or joy.