The industry term is "mic" - for all the reasons posted previously. It will remain "mic" in the industry - an industry that uses 2 or 3 letter abbreviations (without periods) for most of its technology - CAM, AUD, VID, VHS, DBC, BSP, VHS, VTR, TVN, DVD, ADO, DME, ME, CC, DLT, HD, SD, D1,D2,D3,D5,D9, DVC,DV, SX and hundreds of others.

Whether it is a proper abbreviation or politically correct really doesn't matter.   If you want to BS your way into sounding like a pro (or a geek) use MIC.