* Quad-: This is the most common prefix for four. It comes from the Latin word "quadri" meaning "four".
* Quadrangle (a four-sided figure)
* Quadrilateral (a four-sided polygon)
* Quadruped (an animal with four feet)
* Quadruple (to multiply by four)
* Tetra-: This prefix also comes from Greek, meaning "four".
* Tetrahedron (a four-sided solid)
* Tetrad (a group of four)
* Tetrameter (a line of poetry with four metrical feet)
* Quar-: This prefix is less common but still used, particularly in some words related to money.
* Quartet (a group of four musicians)
* Quarter (one-fourth of something)
There are other words with less common prefixes for "four" in specific contexts. For example, "bi-quadratic" refers to a mathematical equation with a fourth-degree term.