n. (Chem.) Any one of the set of elements which, as contrasted with the metals, possess, produce, or receive, acid rather than basic properties; a metalloid; as, oxygen, sulphur, and chlorine are nonmetals. [ 1913 Webster ]
a. 1. Not metallic. [ 1913 Webster ]
2. (Chem.) Resembling, or possessing the properties of, a nonmetal or metalloid; as, sulphur is a nonmetallic element. [ 1913 Webster ]