A person that is so fat or overweight that they got rolls on their back. the type you would usually see on a persons stomach.

A layer of buttery cheese commonly found on a sorostitute's back, just above her waist that usually shows signs of dunlap disease and may or may not be accompanied by a large stripper tattoo. This type of fatback is mostly caused from drinking beer and eating large pizzas all by themselves. Possibly a major portion of their freshman fifteen.

A referal of a females backside or booty, appealing to the opposite sex, which is man. (No Males should have a fatback. Females are strickly forbidden to use this world unless your gay).

When you hit somebody’s back with your hand cupped and it make a loud ass noice

the pubis area in which your pubic hair grows; the area above the penis or labia

A girl who is rather heavy, yet not totally obese, in a fairly sexy way. It is a common term of endearment for the larger girls, who are not fat, but sexy.

A person with a giant back, but an incredibly small penis. To make up for insecurities resulting from a case of babydick, a fat back will overcompensate and take advantage of any oppurtunity to brag about his or her hugeness, back or otherwise.