Motoscafo armato silurante (torpedo-armed motorboat), alternatively Motoscafo antisommergibili (anti-submarine motorboat) and commonly abbreviated as MAS, was a class of fast torpedo-armed vessels used by the Regia Marina (Italian Royal Navy) during World War I and World War II. Originally, "MAS" referred to motobarca armata SVAN (armed motorboat SVAN), Società Veneziana Automobili Navali (Naval Automobile Society of Venice).[1]
The MAS were petrol-engined planing boats with displacements of 20–30 tonnes (depending on the class), a 10-man crew and armament composed of two torpedoes, heavy machine guns and occasionally a 37 mm or 20 mm cannon.
In the context of the unit title Flottiglia MAS (assault craft flotilla; the most famous of which was the Decima MAS of World War II), the term "MAS" is an acronym for Mezzi d'Assalto (assault craft).