square sail

a sail set beneath a horizontal yard, the normal position of which, when not trimmed to the wind, is directly athwartships.

Origin of square sail

First recorded in 1590–1600

Half an hour later the wind had gone round far enough for the square-sail to be used to advantage, and it was accordingly hoisted.

The Queen's Cup |G. A. Henty
We hoisted our square-sail and wet our other sails, but the schooner gained upon us rapidly.

Jack in the Forecastle |John Sherburne Sleeper
The term is applied to any fore-and-aft vessels setting a square-sail, flying, below the lower cross-trees.

The Sailor's Word-Book |William Henry Smyth
Is full schooner-rigged, but carries a square-topsail on the fore-mast; the fore-sail not bent, but set as a square-sail.

The Sailor's Word-Book |William Henry Smyth

When round, they came again upon even terms, as 'Livonia' had to luff and to lower her square-sail.

Yachting Vol. 1 |Various.

square sail

nautical a rectangular or square sail set on a horizontal yard rigged more or less athwartships