Definition of "mainmast"

O, the most piteous cry of the poor souls! sometimes to see ’em, and not to see ’em; now the ship boring the moon with her main-mast, and anon swallowed with yest and froth, as you’ld thrust a cork into a hogshead.

c. 1610–1611 (date written), William Shakespeare, “The Winters Tale”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act III, scene iii]

Then turning to his first Minister, who waited behind him with a white Staff near as tall as the Main-mast of the Royal Soveraign, he observed how contemptible a thing was human Grandeur, which could be mimicked by such diminutive Insects as I […]

1726 October 28, [Jonathan Swift], “A Great Storm Described, the Long-Boat Sent to Fetch Water, the Author Goes with It to Discover the Country. […]”, in Travels into Several Remote Nations of the World. […] [Gulliver’s Travels], volume I, London: […] Benj[amin] Motte, […], part II (A Voyage to Brobdingnag), page 58

When we were in the latitude of Martinico, and near making the land, one morning we had a brisk gale of wind, and, carrying too much sail, the main-mast went over the side.

1789, Olaudah Equiano, chapter 11, in The Interesting Narrative of the Life of Olaudah Equiano‎

The try-works are planted between the foremast and mainmast, the most roomy part of the deck.

1851 November 14, Herman Melville, chapter 96, in Moby-Dick; or, The Whale, 1st American edition, New York, N.Y.: Harper & Brothers; London: Richard Bentley

[…] skating farther than their wont that day they reached that part of the river where the ships had anchored and been frozen in midstream. Among them was the ship of the Muscovite Embassy flying its double-headed black eagle from the main mast, which was hung with many-coloured icicles several yards in length.

1928, Virginia Woolf, Orlando: A Biography, London: The Hogarth Press; republished as Orlando: A Biography (eBook no. 0200331h.html), Australia: Project Gutenberg Australia, July 2015