(idiomatic) One who gets up early in the morning or goes to bed early.

plural of day trader

(computing) Alternative spelling of zero-day.

(computing) Alternative spelling of zero-day.

(chiefly African-American Vernacular, Yorkshire, nonstandard) Alternative form of back in the day

On any occasion; in any circumstances.

plural of day fine

Alternative spelling of day fine

A unit of fine payment based on the offender's daily personal income. The number of day fines depends on the gravity of offence.

(US, dated) Memorial Day