"Square-riggers" have primarily square sails, but the jib sails are triangular.
Well, back then people used the traditional square sails. So when the Caravel was built they used triangular sails instead of the traditional square sails which made the ship able to sail against the wind.
Hispaniola is the ship he sails to Treasure Island
Lateen sails were adapted from the Mediterranean region.
They do because before ships had motors to make them move in the water. With the sails the wind would push the ship.
They are referred to as four-cornered sails.
"Four-cornered".
Square sails are square
I don't think there is another name other than blade.
Square sails are referred to as four-cornered sails.
Trapezoidal, actually. But the square sails were called square sails. Lateen or square could be referred to as yards.
"Square-riggers" have primarily square sails, but the jib sails are triangular.
"Square sails" which are not really square, were/are referred to as four-cornered sails.
"Four-cornered" sails were (are) square.
Square sails (rectangular) were (are) called four-cornered sails.
Square sails are referred to as four-cornered sails.
Historically, they are referred to as "four-cornered" sails.