Birth'day1, n.
n. [birth and day.] 1. The day in which any person is born; day of origin or commencement.
Those barbarous ages past, succeeded next The birthday of invention. Cooper.
Sense 2. The same day of the month, in which a person was born, in every succeeding year; the anniversary of one's birth.
This is my birthday, as this very day was Cassius born. Shak.