1753, "a sum (of cash) put in, a sharing, contribution," from verbal phrase; see in (adv.) + put (v.). Meaning "energy supplied to a device or machine" is from 1902, later of electronic devices; computing sense of "data fed into a machine" is from 1948, though this is perhaps from the verb in the computing sense.
input (v.)
late 14c., "put on, impose," from in (adv.) + put (v.). Modern sense "feed data into a machine" is from 1946, a new formation from the same elements.
we would appreciate input from our users on how we can improve our software
inoperative
inopportune
inordinate
inorganic
in-patient
input
inquest
inquiline
inquire
inquirer
inquiring