Know how to use "fewer" and "less"? Find out.
Old English græg (Mercian grei), from Proto-Germanic *grisja- "gray" (cf. Old Norse grar, Old Frisian gre, Middle Dutch gra, Dutch graw, Old High German grao, German grau), with no certain cognates outside Germanic. French gris, Spanish gris, Italian grigio, Medieval Latin griseus are Germanic loan-words.
The distinction between British grey and U.S. gray developed 20c. The noun is c.1200, from the adjective. Gray as figurative for "Southern troops in the U.S. Civil War" is first recorded 1863, in reference to their uniform color. Expression the gray mare is the better horse in reference to households ruled by wives is recorded from 1540s. The verb is 1610s (with an isolated instance from late 14c.). Related: Grayed; graying.
A unit for a specific absorbed dose of radiation equal to 100 rads.
Gray (grā), Henry. 1825?-1861.
British anatomist whose work Anatomy, Descriptive and Surgical (1858), known as Gray's Anatomy, remains a standard text.
unit of absorbed dose of ionizing radiation, defined in the 1980s by the International Commission on Radiation Units and Measurements. One gray is equal approximately to the absorbed dose delivered when the energy per unit mass imparted to matter by ionizing radiation is one joule per kilogram. As a unit of measure, the gray is coherent with the units of measure in the International System of Units (SI). The gray replaced the rad, which was not coherent with the SI system. One gray equals 100 rads