legal Definition of floor 1 a: a main level space (as in a stock exchange or legislative chamber) distinguished from a platform or gallery b: members of an assembly
Learner's definition of BIRTHDAY. [count]. 1. : the day when someone was born or the anniversary of that day. â often used before another noun.
Examples of birthday in a sentence. 1  Her birthday is September 30th. 2  Today is his 21st birthday. 3  The company just celebrated its 50th birthday.