Just out  of curiosity what is the definition of MLM mom?

It's someone who thinks she is earning extra income but in reality, she's actually losing money most of the time. These companies are basically like pyramid schemes. They are successful as long as the top members keep signing up new recruits who pay upfront costs up the chain to those who get them to join. Eventually, no new recruits join or not enough join to keep the chain going so the pyramid collapses and it leaves those on top with all the profits while everybody else is out of a lot of money.

Multi-level Marketing.    The sort of woman who sells stuff to her friends and neighbours.  Candles or clothes or cosmetics, normally.

I've only heard MLM stand for multi-level marketing. Usually, those involved in it are stay-at-home moms.