Definition of "once" in English

adverb

1. (frequency) One and only one time.

   • I have only once eaten pizza.

2. (temporal location) Formerly; during some period in the past.

   • He was once the most handsome man around.
   • I once had a motorbicycle.
   • Once I didn't drive a big car, but now I own an all-terrain 4WD.
   • Wang notes that flowers have rooted and grow in the area once covered with ice.

3. (chiefly obsolete) At any time; ever.

   • If the facts once became known, we'd be in trouble.

4. (obsolete) One day, someday.

5. (mathematics) Multiplied by one: indicating that a number is multiplied by one.

   • Once three is three.

conjunction

1. As soon as; when; after.

   • Near-synonym: immediately
   • We'll get a move on once we find the damn car keys!
   • Once you have obtained the elven bow, return to the troll bridge and trade it for the sleeping potion.
   • Once he is married, he will be able to claim the inheritance.

noun

1. Obsolete form of ounce.