coetaneous (adj.)

"having the same age as another, beginning to exist at the same time," c. 1600, from Late Latin coaetanus "one of the same age," from assimilated form of Latin com "with, together with" (see com-) + aetas "age" (from PIE root *aiw- "vital force, life; long life, eternity") + adjectival suffix -aneus. Related: Coetaneously.