English
interquintile
From inter- + quintile.
Proto-Indo-European *h₁én ‘in’
Proto-Indo-European *h₁entér ‘between’
Proto-Italic *n̥ter ‘between’
Latin inter ‘between’
English inter-
Today it means
adj Between (adjacent) quintiles
Language periods are conventional ranges, not dates for this word.
Etymograph / interquintile