Trapezoidal, actually. But the square sails were called square sails. Lateen or square could be referred to as yards.
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They were referred to as "four-cornered" sails.
The caravel was created by Prince Henry, a portuguese explorer. He needed a ship that would be able to sail near the rocky coast of Africa and connect him to the Indies for trade. ... The first improvement were its lateen sails. They were triangular sails that helped travel against wind and increased the speed of the ship.
I'm not an expert, but I believe you can sail closer to the wind with a lateen-rigged sail than with square sails.
Lateen Sails
Triangular-shaped sails helped catch wind from the sides and rear.
Square sails are not truly square but rectangular with a longer long side on the bottom perimeter of the sail. They were and are referred to as "four-cornered" sails.
One type is the "lateen sail", but there are also jibs; Genoa & spinnaker.
A caravel is one of the ships Columbus sailed in that has 2-4 masts and lateen sails.
Instruments: Lateen sails Improvments: Caravel
Lanteen sails were used by the ancient Egyptians and many other Mediterranean countries too