Dictionary.com
Thesaurus.com

Robertson screw

British  
/ ˈrɒbətsən /

noun

  1. a screw having a square hole in the head into which a screwdriver with a square point ( Robertson screwdriver ( trademark )) fits

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of Robertson screw

C20: after its inventor P. L. Robertson (1896–1951), a Canadian industrialist