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).
New; recent: neonatal.
New and different: Neo-Freudian.
New and abnormal: neoplasm.