The term has a couple of meaning depending on the context in which it is used.
1.It can be used to refer to someone who is full bodied, usually women.
“You have got meat in all the right places, knorrox”
2.It is a term used to refer to “stocko“.
“Did you see those girls at the club last night, knorrox.”
It is believed that the term was coined because the food brand Knorrox produces meat flavouring stock cubes.