One who is employed, or otherwise engaged in an activity, on a full-time basis.

A small version of an hourglass used to time the boiling of an egg. / (by extension) A timer that can be set to sound an alarm after a certain amount of time; a kitchen timer.

(Scrabble) A word that covers two triple-word squares, so that the overall value of the letters is multiplied by nine.

A major player in the field in question: someone who is in the big time

a person engaging in any activity for the first time

An electronic or software timer used to detect and recover from computer malfunctions by generating a timeout signal if it is not periodically reset by the system.

Alternative spelling of egg timer

(soccer, ice hockey) A shot, made from a teammate's pass, which is not stopped before shooting.

A chess clock.

One who works only half the usual time, especially (historical) a pupil in an elementary school allowed to be absent half the school-day at some employment.