Rex
A surname that likely began as a nickname from Latin rex, meaning “king,” though some sources also connect it to shortened forms of Richard.
The #5,975 most common surname in the United States (2010 Census) — about 1 in every 53,620 Americans shares it.
Etymology
Rex is the Latin word for “king,” and in some surname traditions it was likely used as a nickname or as a title-like byname. Older English surname writers also suggested a more ordinary nickname route: Rex as a shortened form of Richard, through forms such as Rick, Ricks, and Recks. The evidence in early records is limited, so both explanations have been treated as plausible.
History
19th-century surname dictionaries record early bearers such as Adam Rex and John Rex, showing the name in medieval English use. The Latin-title explanation may have appealed because rex was a familiar learned word, while the Richard-shortening explanation fits broader English surname patterns. The name remains uncommon in the United States.
Origin
Regions
Variant spellings
Fun fact
One early surname writer even wondered whether Rex could have come from someone acting the part of a king in a miracle play.
From the historical record
“REWES, genit., and pi., of Rew (Eng.), q.v. REX (Lat.) King . [Lat. rex] John 'Rex.—Hund. Rolls. (Teut.) for Ricks, q.v. REX(S)TREW for Raokstraw, q.v. REY (Eng. and Scand.) for Ray, q.v. (Fr.-Lat.) King [O.Fr. rey, rei (^mod. roi), Lat. reg-em, ace. of rex, a king]”
— Surnames of the United Kingdom: a concise etymological dictionary (2 vols in 1)