brevet
Concise Oxford English Dictionary © 2008 Oxford University Press:
brevet /ˈbrɛvɪt/
▶noun a former type of military commission conferred especially for outstanding service, by which an officer was promoted to a higher rank without the corresponding pay. ▶verb (brevets, breveting or brevetting, breveted or brevetted) confer a brevet rank on.
– origin ME (denoting an official letter): from OFr. brievet ‘little letter’, dimin. of bref.
'brevet' also found in these Oxford entries:

