English

subinterest

From sub- + interest.

Proto-Indo-European *upó ‘up; from below’

Proto-Italic *supo ‘under’

Latin sub ‘under, beneath, below’

English sub-

Proto-Indo-European *h₁es- ‘to be’

…

Latin intersum ‘to be between; to concern’

Medieval Latin intersum ‘to concern’

Old French interesse

Middle English interest

Today it means

noun subsidiary interest

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

Etymograph / subinterest