The name Blithe is of English origin and means "Happy." The origin is the culture in which the name originated, or in the case of a word--the language in which it most appears.
"Blithe Spirit" play by Noel Coward
Blithe is on 463 BN name lists Blithe is currently not ranked on the BN charts Blithe is currently not ranked in U.S. births
Blithe 
