- a combining form meaning “new,” “recent,” “revived,” “modified,” used in the formation of compound words: neo-Darwinism; Neolithic; neoorthodoxy; neophyte.
- Chemistry. a combining form used in the names of isomers having a carbon atom attached to four carbon atoms: neoarsphenamine.
- (sometimes capital) new, recent, or a new or modern form or developmentneoclassicism; neocolonialism
- (usually capital) the most recent subdivision of a geological periodNeogene
word-forming element meaning “new, recent,” used in a seemingly endless number of adjectives and nouns, mostly coined since c.1880, from Greek neo-, comb. form of neos “new, young, youthful; fresh, strange; lately, just now,” from PIE root *newo- (see new). pref.
- New; recent:neonatal.
- New and different:Neo-Freudian.
- New and abnormal:neoplasm.