(not-comparable) Of chief or leading importance; prime, principal.
(not-comparable) Chief, most important, or principal in extent, size, or strength; consisting of the largest part.
(archaic, not-comparable, usually) Full, sheer, undivided.
(dialectal, not-comparable) Big; angry.
(not-comparable) Belonging to or connected with the principal mast in a vessel.
(not-comparable, obsolete) Great in size or degree; important, powerful, strong, vast.

Exceedingly, extremely, greatly, mightily, very, very much.

(abbreviation, alt-of, ellipsis, slang, transitive) Ellipsis of mainline (“to inject (a drug) directly into a vein”).
(transitive) To mainly play a specific character or side, or with specific equipment, during a game.
(obsolete) To convert (a road) into a main or primary road.

That which is chief or principal; the chief or main portion; the bulk, the greater part, gross.
That which is chief or principal; the chief or main portion; the bulk, the greater part, gross.
(Internet) That which is chief or principal; the chief or main portion; the bulk, the greater part, gross.
A large cable or pipe providing utility service to an area or a building, such as a water main or electric main.
(abbreviation, alt-of, ellipsis, informal) Ellipsis of main course (“the principal dish of a meal”).
(poetic) The high seas.
(US, archaic, dialectal) The mainland.
(abbreviation, alt-of, ellipsis) Ellipsis of mainsail.
(obsolete) Force, power, strength, violent effort.

(obsolete) A hand or match in a game of dice.
(obsolete) The largest throw in a match at dice; in the game of hazard, a number from one to nine called out by a person before the dice are thrown.
(obsolete) A stake played for at dice.
(obsolete) A sporting contest or match, especially a cockfighting match.
A banker's shovel for coins.

A basket for gathering grapes.