quadrate

Sharp-eyed readers may recognize the "quad" in "quadrate," suggesting the number four. "Quadrate" is in fact a relative of Latin quattuor, meaning "four," though its direct line of descent links to quadrum, meaning "square." Other descendants of "quadrum" in English include "quadrille" (a square dance for four couples), "quarrel" (a square-headed bolt or arrow), and "quarry" (a place where large amounts of stone are dug out of the ground); the latter of these can be traced back to a Latin word meaning "squared stone." "Quadrate," incidentally, can also be used in much more specific senses to describe a type of heraldic cross or a portion of the skull in some vertebrates.