"characterized by the use of push-buttons," 1945, originally of military systems, earlier "operated by push-buttons" (1903), from push-button (n.), 1865, from push (v.) + button (n.). Earlier was press-button (1892), from the noun (1879).
electronics A roughly fingertip-sized plastic cover attached to a spring-loaded, normally-open switch, which, when pressed, closes the switch. Typical examples are the keys on a computer or calculator keyboard and mouse buttons. (1997-07-07)