In statistics, the mode is the value that has the largest number of observations, namely the most frequent value or values. The mode is not necessarily unique, unlike the arithmetic mean and the median. It is most useful when the values or observations are not numeric: for example, while the mode of {1, 2, 2, 2, 3, 9} is 2, the mode of {apple, apple, banana, orange, orange, orange, peach} is orange.
In computer software, 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 command line interface.)
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 acoustics, a mode is one of the possible patterns of vibration, analogous to waveguide and cavity modes, only that electrical and magnetical fields are replaced by velocity and displacement. Each mode has a characteristic vibrational frequency and damping.
An example of acoustic modes: An "ideal" guitar string of length L, fixed at both ends, will have modes in the shape of sin(n*x*pi/L), where n is the mode number.
