Mk

Mk is the slang used for saying Okay or "you okay" in a question. So say you asked someone to pick up onions, you would say "Pick up some onions, mk?"
You pronounce and say it the way that the M is not pronounced like the alphabet, but the way it would be pronounced in a word, for example the M at the beginning of Megan. The K is pronounced the alphabet way, however, i.e. not in the way you would say "kite". It also can be used to ask someone to do something, as in "Pick up Tommy, mk?" Instead of "Can you pick up Tommy?"

I'm going to the gym, mk?
Pick up Tommy, mk?
Let's go to school, mk?"

MK

An abbriviation of the name Mihael Keehl, which is the real name of the character Mello in the anime/manga, Death Note.

Person 1: DUDE! MK died in the Death Note episode last week!
Person 2: MK?
Person 1: Mihael Keehl!
Person 2:....Who?
Person 1:...Mello. Retard.

MK

nickname for Mary-Kate Olsen. Used by fans and Mary-Kate's friends.

MK's sunglasses are bigger than her head.

MK

A community college in MoCo, MD-Montgomery College

AKA Harvard on the Pike

Tracey: Where does she go to school?
Nicole: MK-not smart enough for UMD.

MK

A hobbit that leaves feet hair and constantly clogs any toilet by leaving mini dead gerbils.

Why did you go MK in the bathroom?

mks

Short for marcus
He's a jew

mks is a kid I know. He's jewish.

MK

An abbreviation for "missionary kid."

Her parents are Christian missionaries and she grew up in Peru as an MK.