from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Sheathed with iron plates for protection.
- adj. Rigid; fixed: an ironclad rule.
- n. A 19th-century warship having sides armored with metal plates.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Covered with iron, steel, or some metal, armor-plated
- adj. Solid or certain; not able to be disputed or questioned; irrefutable.
- n. A metal-plated ship, vessel, or vehicle
- n. An armor-plated warship.
from the GNU version of the Collaborative International Dictionary of English
- adj. Clad in iron; protected or covered with iron, as a vessel for naval warfare.
- adj. Rigorous; unbreakable; severe; exacting; inflexible.
- n. A naval vessel having the parts above water covered and protected by iron or steel usually in large plates closely joined and made sufficiently thick and strong to resist heavy shot. Modern naval vessels are made of steel throughout, and this term is only used in historical contexts.
- adj. having an outer covering of iron or steel.
- adj. so strong or secure as to be unbreakable.
from The Century Dictionary and Cyclopedia
- Covered or cased with iron plates, as a vessel for naval warfare; armor-plated.
- Figuratively, very rigid or strict; constructed, as a form of words, so as to allow no evasion or escape, or permit no flaw to be detected.
- n. A naval vessel cased or covered wholly or partly with thick iron or steel plates, generally having a heavy backing of wood, so armored to resist projectiles or the attacks of rams or other armored vessels.
- Noting an electrical apparatus or machine in which the iron part of the structure completely or partly surrounds and thereby mechanically protects the electric conductors: as, an iron-clad armature, one having the conductors embedded in slots or holes.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a wooden warship of the 19th century that is plated with iron or steel armor
- adj. sheathed in iron plates for protection
- adj. inflexibly entrenched and unchangeable
From iron + clad (Wiktionary)