Twice means two times. It can also suggest that something is double in amount or degree.
From Old English "twīwa" or "twiga" meaning two times, built on the root for "two." It parallels "once" (one time) and "thrice" (three times), though "thrice" is now rare.
English used to regularly say "thrice" for three times, just like "twice," but that one mostly disappeared in everyday speech. The pattern shows how language can keep some members of a family of words and quietly drop others.
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