Rebasing

In computing, rebasing is one of the following:

Rebasing is the process of creating a shared library image in such a way that it is guaranteed to use virtual memory without conflicting with any other shared libraries loadable in the system.

IBM VM/370 Discontinuous Saved Segments (DCSS) were an early example of this technique, though not called rebasing. The technique is used extensively on Win32 platforms to avoid the overhead of address relocation of system DLLs by the loader.

Some security extensions to Linux/x86 use rebasing to force the use of code addresses below 0x00ffffff in order to introduce a 0x00 byte into all code pointers; this eliminates a certain class of buffer overflow security problems related to improper checking of null-terminated strings, common in the C programming language.

...
Wikipedia