n. [ Nitroso- + -yl. ] (Chem.) The radical -NO, called also the nitroso group. The term is sometimes loosely used to designate certain nitro compounds; as, nitrosyl sulphuric acid. Used also adjectively. [ 1913 Webster ]
a. (Chem.) Of, pertaining to, or containing, nitrosyl; as, nitrosylic acid. [ 1913 Webster ]
(Chem.) A prefix (also used adjectively) designating the group or radical -NO, called the nitroso group, or its compounds. [ 1913 Webster ]