Pronunciation: (sit'u-dl, -u-del"), [key]
1. a fortress that commands a city and is used in the control of the inhabitants and in defense during attack or siege.
2. any strongly fortified place; stronghold.
3. (formerly) a heavily armored structure on a warship, for protecting the engines, magazines, etc.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.