The story
- Proto-West Germanic · inherited from*middjahrif
- Old English · inherited frommidrif
- Middle English · inherited frommidref
- English todaymidriff
From Middle English midref, mydrif, from Old English midrif, midhrif (“the midriff; diaphragm”), from Proto-West Germanic *middjahrif. Equivalent to mid- + riff.
Etymology from Wiktionary, CC BY-SA 4.0.