neonatal (adj.)

late 14c., "of or pertaining to birthdays;" mid-15c., "of or pertaining to one's birth," from Latin natalis "pertaining to birth or origin," from natus, past participle of nasci "to be born" (Old Latin gnasci), from PIE root *gene- "give birth, beget." It is the learned form of Noel, which was the French vernacular word.

word-forming element meaning "new, young, recent," used in a seemingly endless number of adjectives and nouns, mostly coined since c. 1880, from Greek neos "new, young, youthful; fresh, strange; lately, just now," from PIE root *newo- (see new). In the physical sciences, caeno-, ceno- is used in the same sense. Paleo- is opposed to both.