Etymology tree Proto-Indo-European *né Proto-Indo-European *n̥- Proto-Italic *n̥- Latin in-bor. Middle English in- English in- Proto-Indo-European *ḱe? Proto-Indo-European *ḱóm Proto-Italic *kom Proto-Italic *kom- Latin con- Latin haereō Latin cohaereō Latin cohaerēnsder. Middle French coherentder. English coherent English incoherent From in- + coherent.