(1) A piece of equipment. Devices can be workstations, printers, disc drives, tape units, or remote systems.
(2) In the AIX operating system, a valuator, button, or the keyboard. Buttons have values of 0 or 1 (up or down); valuators return values in a range, and the keyboard returns ASCII values.
(3) In UML modeling, a type of node that represents a physical computational resource in a system, such as an application server.