Definition - What does Mode mean?
In computer interface design, a mode is a user setting in which the same input produces different results in different modes. A mode serves as a mechanism that provides users with added functionality features that would not otherwise fit into a program's main operational flow.
Examples of commonly used user interface (UI) modes are the Caps Lock and Num Lock keys on a computer keyboard.
Techopedia explains Mode
Mode proponents claim easy user adaptability. However, critics have observed that modes lead to errors, such as when a user not remember to reverse a mode after activation. Thus, designers are working on creating more obvious modes and user techniques that facilitate mode error reversal.
An interface without modes, which renders mode errors impossible, is known as a modeless interface.