'Catamaran' definitions:

Definition of 'catamaran'

noun

A sailboat with two parallel hulls held together by single deck

From: GCIDE

Catamaran \Cat`a*ma*ran"\, n. [The native East Indian name.]
1. A kind of raft or float, consisting of two or more logs or pieces of wood lashed together, and moved by paddles or sail; -- used as a surf boat and for other purposes on the coasts of the East and West Indies and South America. Modified forms are much used in the lumber regions of North America, and at life-saving stations. [1913 Webster]
2. Any vessel with twin hulls, whether propelled by sails or by steam; esp., one of a class of double-hulled pleasure boats remarkable for speed. [1913 Webster]
3. A kind of fire raft or torpedo bat. [1913 Webster]
The incendiary rafts prepared by Sir Sidney Smith for destroying the French flotilla at Boulogne,
1804, were called catamarans. --Knight. [1913 Webster]
4. A quarrelsome woman; a scold. [Colloq.] [1913 Webster]