relocation
A note the assembler leaves in an object file saying: these bytes are not finished; fill in the address of this symbol once it is known.
A relocation is a deferred fix-up: a location in a section whose final value depends on an address the assembler cannot know (another file's symbol, or the final position of a section), to be computed and written by the linker or, for some, by the dynamic linker at load time.