MAINSAIL

mainsail

(noun) the lowermost sail on the mainmast

Source: WordNet® 3.1

Etymology

Noun

mainsail (plural mainsails)

(nautical) The largest (or only) sail on a sailing vessel.

Synonyms

• main (“mainsail”)

Source: Wiktionary

Main"sail`, n. (Naut.)

Definition: The principal sail in a ship or other vessel. [They] hoised up the mainsail to the wind. Acts xxvii. 40.

Note: The mainsail of a ship is extended upon a yard attached to the mainmast, and that of a sloop or schooner upon the boom.

Source: Webster’s Unabridged Dictionary 1913 Edition