Etymology

From Proto-Iranian, from Proto-Indo-Iranian, from Proto-Indo-European *swéḱs. Compare Persian شش ‎(šeš), Avestan 𐬑𐬴𐬎𐬎𐬀𐬱 ‎(χšvaš), Sanskrit षष् ‎(ṣáṣ), Hindi छह ‎(chah), Spanish seis, German sechs, Lithuanian šešì, Russian шесть ‎(šestʹ), Armenian վեց ‎(vecʿ), Ancient Greek ἕξ ‎(héx).