What are yemens?

Some articles on yemen:

North Yemen
... North Yemen is a term used to designate the Yemen Arab Republic (1962–1990), its predecessor, the Mutawakkilite Kingdom of Yemen (1918–1962 ... Neither state ever self-designated as "North Yemen" and the term only came into general use when the Federation of South Arabia gained independence as the People's Republic of Yemen in 1967 making such a ... Prior to 1967, both states were known in short form simply as "Yemen." In 1970, South Yemen changed its name to the People's Democratic Republic of Yemen ...