Abbott-Smith Manual Greek Lexicon
ὀκταήμερος (G3637)
1 *† ὀκταήμερος , -ον ( ὀκτώ , ἡμέρα ), of the eighth day , eight days old : c. dat. ref., περιτομῇ ὀ. , Phl 3:5 (words of this class denote duration , cf. τεταρταῖος ).†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain