From Italian 'fregata' (fast vessel), possibly from Greek 'aphraktos' (undecked ship) — evolving to describe ever-larger warships.
A warship, historically smaller and faster than a ship of the line, used for escort, patrol, and reconnaissance; in modern navies, a medium-sized warship.
From French 'frégate,' from Italian 'fregata' (a type of fast warship), of uncertain ultimate origin. The most widely accepted theory traces it to an older Mediterranean word, possibly from Greek 'aphraktos' (undecked vessel), from 'a-' (not) and 'phrassein' (to fence in, to enclose). The term originally referred to a small, fast, open vessel in the Mediterranean, before being adopted for progressively larger warships as naval architecture evolved. Key
The frigatebird, a large tropical seabird, was named after the warship because of its speed, agility, and reputation for piracy — frigatebirds harass other seabirds in flight until they drop their catch, then snatch the food mid-air. Sailors saw the parallel between the bird's aerial piracy and the frigate's role as a fast raider.