An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A cardinal number, five plus one.

M.E. six, sex; O.E. siex, syx, seox, sex, from P.Gmc. *sekhs (cf. O.S. seks, O.N., O.Fris. sex, M.Du. sesse, Du. zes, O.H.G. sehs, Ger. sechs, Goth. saihs), from PIE *seks-, cognate with Pers. šeš, as below.

Šeš, from Mid.Pers. šaš; Av. xšuuaš- "six;" cf. Skt. sás- "six;" Gk. hex; L. sex (Fr. six; Sp. seis); O.C.S. sesti; Lith. sesi; O.Ir. se; Welsh chwech; E. six, as above.

A cardinal number, ten times six. → sexagesimal.

M.E.; O.E. sixtig, from → six + -tig a suffix of numerals denoting multiples of ten.

Šast "sixty;" Mid.Pers. šast "sixty;" Av. xšuuašti- "sixty;" cf. Skt. sasti- "six;" L. sexaginta "sixty."