late 15c. (Caxton), "capable of movement, capable of being moved, not fixed or stationary," from Old French mobile (14c.), from Latin mobilis "movable, easy to move; loose, not firm," figuratively, "pliable, flexible, susceptible, nimble, quick; changeable, inconstant, fickle," contraction of *movibilis, from movere "to move" (from PIE root *meue- "to push away"). Sociology sense of "able to move into different social levels" is by 1927. Mobile home "large trailer permanently parked and used as a residence" is recorded by 1936. Mobile phone is by 1983.
A long-distance number tapped into an Illinois Bell car telephone glowed red on a display. Satisfied that the digits were correct, I pushed the SEND button on the phone. Familiar beeps and boops emerged from the handset. Then, before a half block of this Chicago suburb had slipped by, I was in contact with my New York office. ["Take-along Telephones," Popular Science, October 1983]