(noun), Poo Of Unusual Size.
Based on the terminology used in the movie The Princess Bride, in reference to the R.O.U.S.'s (Rodents Of Unusual Size) found in the Fire Swamp.
This is an extremely large poo, at least a portion of which exhibits exceptional girth. This type of poo usually exits very slowly and after a stressful episode of exhaustive straining, suddenly drops into the toilet. This is the correct and technical term to use, although this type of doody is often mislabeled as "doodying out a coke can," "crapping out a watermelon," or in general, when someone claimed they shat (past tense) out a friggin' <insert large object name here>.
Note that during a P.O.U.S., you may experience intermittent symptoms of M.W.P.
, (Machete Wielding Poo).
Whew, I'm glad that's over...I just knew I had ripped my butthole open when I dropped that P.O.U.S. earlier.