| A | B |
| quadrangle | a four-sided enclosure |
| quadrant | one out of four equal parts of a circle; one section of a four section coordinate grid |
| quadrennial | happening every four years |
| quadriceps | a muscle group consisting of four muscles that is located along the front of the thigh |
| quadrilateral | a plane figure in geometry that has four sides (including a square, rectangle, rhombus, parellelogram, and trapezoid) |
| quadrilingual | able to speak four languages |
| quadrisect | to dut or divide into four equal parts |
| quadruped | an animal with four feet |
| quadruple | to create four times as much or as many of something |
| quadruplet | a collection or group of four; one of four babies born from the same mother at the same time |