What does "ISO" stand for?

no i am just bad with acryonyms and slang so i dont know what some ppl are saying when they type strange stuff but i think we could make a sticky for slang like this for example
afk=away from keyboard
brb= be right back
brt=be right there
wuw= what you want
wug= what you got
iso=in search of
btw= by the way

also we could possible do an item section where you post abreviations or nick names to the items example are
gf=grand fater colossus sword
wf=windforce hydrabow
doom=doombringer championsword
40/15ias= 40 enhanced damage with 15 ias on one jewel
40/15max=40 enhanced damage with 15 max damage on one jewel
there are alot of other ones but i have to go