A PWAD, short for patch wad, is a WAD containing lumps of data created by a user as an add-on. PWAD lumps are given priority over IWAD lumps in order for PWADs to replace anything that was included in the original game. The PWAD is the most familiar and widespread type of add-on for the Doom games and is typically used to store custom maps, define additional textures, or override or add to the default textures, sprites, sounds, or other data provided by the game's IWAD.