English

hyporachis

From hypo- + rachis.

Proto-Indo-European *upó ‘under, below’

Ancient Greek ὑπό ‘under’

English hypo-

Ancient Greek ῥάχις ‘spine, ridge’

New Latin rhachis ‘axis, rhachis/rachis’

Today it means

noun The downy lower barbs of a feather.

Language periods are conventional ranges, not dates for this word.

Etymograph / hyporachis