Definitions for "Multihull"
Any boat with more than one hull, such as a catamaran or trimaran.
A multihull is a ship or boat with more than one hull. The additional hulls provide stability, typically to hold the vessel upright against the sideways force of the wind on the sails. This is in contrast to monohulls which typically use a keel and/or ballast for this purpose, especially on larger sailboats.