Definition of safe mode in English:

safe mode

noun

  • 1A mode of operation of a weapon, device, etc., in which it is considered safe or unlikely to fail.

  • 2Computing a way of running an operating system or program in which only device drivers, programs, plug-ins, etc., that provide basic functionality are loaded, typically so as to minimize chances of a system crash and to help in the diagnosis of errors or failures.

Origin

1970s; earliest use found in U.S. Patents.