quadrant— The area within a 90° arc; for example, the southwest quadrant encompasses the area between south and west.
quadrupedal— Using four legs for locomotion.
quartzite— A metamorphic rock consisting mainly of quartz, formed by recrystallization of sandstone by regional or thermal metamorphism; a metaquartzite or metamorphosed quartzite is referred to as an orthoquartzite.
Quaternary— Period of the Cenozoic Era of relative geologic time, following the Tertiary Period; also, the corresponding system of rocks. It began 1.7 million years ago and extends to the present. It consists of two epochs: the Pleistocene and the Holocene, or Recent.