Webster's Revised Unabridged Dictionary · 1913

Twice

Twice (twīs) , adverb

[Old English twies (where the s is the adverbial ending; see -wards), twie, Anglo-Saxon twiges, twiwa; akin to twi- (in comp.) two, German zwie-, Old High German zwi-, Icelandic tvī-, Latin bi-, Greek di-, Sanskrit dvi-, and English two. See Two.]

1.
Two times; once and again.
He twice essayed to cast his son in gold. — Dryden
2.
Doubly; in twofold quantity or degree; as, twice the sum; he is twice as fortunate as his neighbor.

Twice is used in the formation of compounds, mostly self-explaining; as, twice-born, twice-conquered, twice-planted, twice-told, and the like.