Meaning and name origin
Sinclair \s(i)-nc-lair, sin-clair\ as a boy's name is pronounced sin-KLARE. It is of English origin, and the meaning of Sinclair is "from Saint-Clair". Based on the name of a place in northern France. See also Santana and Seymour. Authors Sinclair Lewis, Upton Sinclair.
Sinclair is not a popular first name for males but a very popular surname or last name for all people (#1107 out of 88799, Top 1%) (Source: 2000 U.S. Population Census).
Displayed below is a comparison of the popularity of the boy name Sinclair and its variant forms. Popular variation forms ranked in the Top 1000/100 are Santana (#887) and Seymour. (Source: 2014 Birth Name Statistics).