Sidney \s(i)-dney, sid-ney\ as a girl's name (also used as boy's name Sidney), is pronounced SID-nee. It is of Old English origin, and the meaning of Sidney is "wide meadow". Also possibly derived from the Norman French place name Saint Denis. First used as a given name in the 18th century, and popular in the 19th century. See also Sydney.
Sidney has 5 variant forms: Siddeny, Sideny, Sidneigh, Sidni and Sidnie.