spinnaker

A large triangular headsail secured only at the corners, used on sailboats when running before the wind.

A jib-headed racing-sail carried by yachts, set, when running before the wind, on the side opposite to the mainsail.

A large triangular sail set upon a boom, — used when running before the wind.

A supplemental sail to the main sail, especially a triangular one, used on yachts for running before the wind.

a large and usually triangular headsail; carried by a yacht as a headsail when running before the wind