Uncle \Un"cle\, n. An eldery man; -- used chiefly as a kindly or familiar appellation, esp. (Southern U. S.) for a worthy old negro; as, ``Uncle Remus.'' [Colloq.]

Plain old uncle as he [Socrates] was, with his great ears, -- an immense talker. --Emerson.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Uncle \Un"cle\, n. [OE. uncle, OF. oncle, uncle, F. oncle, fr. L. avunculus a maternal uncle, dim. of avus a grandfather; akin to Lith. avynas uncle, Goth. aw? grandmother, Icel. [=a]i great grandfather.]

1. The brother of one's father or mother; also applied to an aunt's husband; -- the correlative of aunt in sex, and of nephew and niece in relationship.

2. A pawnbroker. [Slang] --Thackeray.

My uncle, a pawnbroker. [Slang]

Uncle Sam, a humorous appellation given to the United States Government. See Uncle Sam, in Dictionary of Noted Names in Fiction.

Source: Webster's Revised Unabridged Dictionary (1913)