When Robert Hured Gean was born on 20 March 1927, in Tennessee, United States, his father, Robert Lee Gean, was 57 and his mother, Hattie Belle White, was 30. He lived in Civil District 3, Hardin, Tennessee, United States in 1940. He died on 3 July 2000, at the age of 73, and was buried in Hardin, Tennessee, United States.
Most probably a shortened Anglicized form of Irish Ó Géibhinn, itself a shortened form of Ó Géibheannaigh, from géibheannach ‘fettered’.
Alternatively, it could be an Americanized form of GermanGien, which is from a short form of Heinrich .