Real Dictionary

modem
A modem is a device which connects computers or computer systems to the internet.

modem in American English
a device that converts data to a form that can be transmitted, as over communications lines, to equipment where a similar device reconverts it
noun: an electronic device that makes possible the transmission of data to or from a computer via telephone or other communication lines
transitive verb: to send or receive (information, data, or the like) via a modem

modem in British English
noun: a device for connecting two computers by a telephone line, consisting of a modulator that converts computer signals into audio signals and a corresponding demodulator

modem in Electrical Engineering
noun: A modem is a hardware device that converts digital computer data into analog tones that can be transmitted over dial-up telephone circuits.