1 a the brother of one's father or mother. b an aunt's husband.
2 colloq. a name given by children to a male family friend.
3 sl. esp. hist. a pawnbroker.
Phrases and idioms:
Uncle Sam colloq. the federal government or citizens of the US (will fight for Uncle Sam). Uncle Tom derog. a Black man considered to be servile, cringing, etc. (from the hero of H. B. Stowe's Uncle Tom's Cabin, 1852).
Etymology: ME f. AF uncle, OF oncle f. LL aunculus f. L avunculus maternal uncle: see AVUNCULAR
Useful english dictionary. 2012.