Mode

Mode

In statistics, the mode is the value that has the largest number of observations. The mode is not necessarily unique, unlike the arithmetic mean and the median.

In music a mode is a kind of scale; see musical mode.

In computer science, a mode is distinct method of operation within a computer program.

Three popular examples of software employing modes:

vi--has one mode for inserting text, and a separate mode for inserting commands. Some people also call VI's ability to line-edit a "mode" (even though it is launched outside of VI's normal interface, by invoking "ex" from the operating system's CLI.)
Emacs--has many modes that can be evoked based on file type to more easily edit files of a certain type. Modes are written in Emacs' LISP, and all modes may not be included with all versions.

CIOS (Cisco Internetworking Operating System)-- in order to gain the privilege to execute certain commands, you must enter a certain mode that allows you to execute that command.

In a waveguide or cavity[?] the mode is one of the possible patterns of electromagnetic field. Available patterns are derived from Maxwell's equations and the applicable boundary conditions[?].

An example of waveguide mode: fiber optic mode.
An example of cavity[?] mode: laser mode.