Original: NCIS was originally referred to as Navy NCIS during Season 1; however, "Navy" was later dropped from the title as it was redundant. NCIS was joined in its seventh season by a spin-off series, NCIS: Los Angeles, starring Chris O'Donnell and LL Cool J.
Simplified: NCIS (also called NCIS: Naval Criminal Investigative Service) is a drama television series on CBS.