English
heptadecad
From hepta- + decad.
Proto-Indo-European *septḿ̥ ‘seven’
Proto-Hellenic *heptə́ ‘seven’
Ancient Greek ἑπτά ‘seven’
English hepta-
Today it means
noun A group of seven decads arranged to produce twenty-four tones
Language periods are conventional ranges, not dates for this word.
Etymograph / heptadecad