Pronunciation: (pou'ur-ful), [key]
1. having or exerting great power or force.
2. physically strong, as a person: a large, powerful athlete.
3. producing great physical effects, as a machine or a blow.
4. potent; efficacious: a powerful drug.
5. having great effectiveness, as a speech, speaker, description, reason, etc.
6. having great power, authority, or influence; mighty: a powerful nation.
7. Chiefly South Midland and Southern U.S.great in number or amount: a powerful lot of money.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.