[orig. from BASIC's 'CHAIN' statement]
vi. To hand off execution to a child or successor without going through the OS command interpreter that invoked it. The state of the parent program is lost and there is no returning to it. Though this facility used to be common on memory-limited micros and is still widely supported for backward compatibility, the jargon usage is semi-obsolescent; in particular, most UNIX programmers will think of this as an exec.
Oppose the more modern subshell.