felsic adjective 1noun 1forms 3 adjective1 •Enriched in minerals predominantly composed of the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium.Much of the southern half of the southeastern body is a mafic syenite, slightly more felsic than the shonkinite. — 1954 noun1 •A rock with such properties.There are also calcalkaline felsics that have highly enriched LREE^([light rare-earth element]) patterns with lower overall abundances. — 1992 formsfelsics · more felsic · most felsic
