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