Pronunciation: (ī'urn-sīd"),[key] —n. 1. a strong person with great power of endurance or resistance.
2. (cap.) an epithet or nickname of Edmund II of England.
3. (cap.) Usually, Ironsides. a. (used with a sing. v.) a nickname of Oliver Cromwell.
b. the soldiers serving under Cromwell.
4. ironsides,(usually used with a sing. v.) a. an ironclad.
b. Eastern U.S.scup.