Done at the proper time or within the proper time limits; prompt. / Happening or appearing at the proper time. / (obsolete) Keeping time or measure.

(archaic) In good time; early, quickly. / (obsolete) At the right time; seasonably. / (law) In compliance with applicable time limits.

from time to time

(tennis) Reminder by the umpire for the players to continue playing after their pause. / The umpire's call in prizefights, etc.

(physics, usually uncountable) A dimension of spacetime with the opposite metric signature to space dimensions; the fourth dimension.

To measure or record the time, duration, or rate of. / To choose when something begins or how long it lasts. / (obsolete) To keep or beat time; to proceed or move in time.

Punctually or according to the schedule. / By installments, payments over a period of time. / (chess) By a player's running out of time.

Punctual or according to schedule.

(idiomatic) On occasion, sometimes.

In a single, continuous period of time. / Simultaneously at each occurrence (of some action).