It stands for "play on words". They often include things like antonyms or synonyms (double meaning), literal interpretion, homophones, etc. They will often be accompanied by a descriptor word or phrase like "sounds of" or "aloud" for homophones; "in other words" "not" "like" "never" for ants. & syns.
In the case of my quickie POW's (yes, hope there will be more) each word or two (generally speaking) of the puzzle corresponds to a letter spelling out the answer and other descriptors can be thrown in refering to the relation of individual letters. Here are two examples I had put in another post.
asp arched shape around kid
--asp is a snake which is "S" shaped
--arched again shape yields "C"
--around or phonetically a round or "O"
--kid meaning to make fun of or tease = "TT"
Put it all together and get SCOTT
Golly, a circular well graded and raised track
--Golly or gee = "G"
--a circular = "O"
--well graded as in a test at school = "A"
--raised track or el = "L"
So you get GOAL