- solid (adj.)
- late 14c., from Old French solide "firm, dense, compact," from Latin solidus "firm, whole, entire" (related to salvus "safe"), from PIE root *sol- "whole" (cf. Greek holos "whole," Latin salus "health;" see safe (adj.)). Slang sense of "wonderful, remarkable" first attested 1920 among jazz musicians. Solid South in U.S. political history is attested from 1858. Solid state as a term in physics is recorded from 1953; meaning "employing transistors (as opposed to vacuum tubes)" is from 1959. Related: Solidly.
- solid (n.)
- late 15c., from solid (adj.).