English

interdorsal

From inter- + dorsal.

Proto-Indo-European *h₁én ‘in’

Proto-Indo-European *h₁entér ‘between’

Proto-Italic *n̥ter ‘between’

Latin inter ‘between’

Proto-Italic *dorsom

Latin dorsum ‘the back’

Medieval Latin dorsālis ‘of or relating to the back’

Middle English dorsal/dorsale

Today it means

adj Between dorsal fins

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

Etymograph / interdorsal