Origin: 1250–1300; Middle English deme(i)nen < Anglo-French, Old French demener, equivalent to de-de- + mener to lead, conduct < Latin mināre to drive, minārī to threaten
"lower in dignity," c.1600, perhaps from de- "down" + mean (adj.) and modeled on debase. Indistinguishable in some uses from obsolete demean (see demeanor) which influenced it and may be its true source.