Definition - What does Fatty mean?
A “fatty” is a slang term for a rolled, marijuana cigarette that is noticeably wider than a typical one. They may be shorter than average as well, or just discernibly broader. Other terms for the same thing include a “fatty joint,” a “fat blunt,” a “Goddie (as in Godfather),” or any other combination except with the alternate spelling “phatty.” Like a “pinner”, there is no agreed upon size for a fatty, though they are not generally less than half a gram and are usually significantly more. Fatties are often rolled for the novelty of their size or specifically to be shared among several people.
Hydrolife explains Fatty
Some smokers like to roll fatties for themselves as a way to not have to roll numerous smaller joints. They simply smoke what they want of the fatty and then re-light the remainder at another time. Some smokers do not prefer fatties because they believe that they burn too fast as compared to pinners or “regular” sized joints. Other smokers of fatties have an issue with canoeing (where one side burns faster than the other usually because of air between the paper and the cannabis). This can be avoided by ensuring an even rolling and by not packing a fatty with moist marijuana.