Latin Meaning: The name Lillian is a Latin baby name. In Latin the meaning of the name Lillian is: Lily (after the flower). Pure. American Meaning: The name Lillian is an American baby name.In American the meaning of the name Lillian is: Lily (after the flower).Pure.he name Lillian is an English baby name. In English the meaning of the name Lillian is: derived from the flower name Lily. Symbol of innocence; purity; beauty.