Lump

Lump refers to any data element inside a WAD or a PK3 archive. Essentially, any file in an archive is a lump.

A map, its BLOCKMAP, SECTORS, SSECTORS, its BEHAVIOR, and any graphics, sounds, or additional data items are all lumps. Text lumps like TEXTURES, MAPINFO, ANIMDEFS are the same. Note, custom lumps with arbitrary names can also be put in a PK3/WAD.

In ZScript lumps can be found, and their contents can be read dynamically with the help of the Wads struct.