From WordNet (r) 2.0 (August 2003) [wn]:
twice
adv 1: two times; "I called her twice"
2: to double the degree; "she was doubly rewarded"; "his eyes
were double bright" [syn: doubly, double]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Twice \Twice\ (tw[imac]s), adv. [OE. twies (where the s is the
adverbial ending; see -wards), twie, AS. twiges, twiwa;
akin to twi- (in comp.) two, G. zwie-, OHG. zwi-, Icel.
tv[imac]-, L. bi-, Gr. di-, Skr. dvi-, and E. two. See
Two.]
[1913 Webster]
1. Two times; once and again.
[1913 Webster]
He twice essayed to cast his son in gold. --Dryden.
[1913 Webster]
2. Doubly; in twofold quantity or degree; as, twice the sum;
he is twice as fortunate as his neighbor.
[1913 Webster]
Note: Twice is used in the formation of compounds, mostly
self-explaining; as, twice-born, twice-conquered,
twice-planted, twice-told, and the like.
[1913 Webster]