- the lowermost sail on a mainmast.
Origin of mainsail
Examples from the Web for mainsail
Historical Examples of mainsail
A mainsail carried by a gaff has two halyards, the throat and peak.
The other two sides of the mainsail are then laid off and pencil lines drawn.
You will note that allowance must be made for hemming the back edge of the mainsail.
I'll try and set the mainsail on her with the remains of the sprit.The Fortunes Of Glencore
Charles James Lever
I've been dreamin' o' night-shirts ever since we bent our mainsail."Captains Courageous"
- nautical the largest and lowermost sail on the mainmast