Modem as in a MOdulator DEModulator, which can converts digital to analog and back. Pretty much everything that transmits digital data over an analog medium either wired or wireless (DSL, Cable, CDMA, GSM, GPRS, 1X, WiFi, etc), could be called a modem.

It's not a modem in the perspective of PC-to-Internet communications, but a modem in the scientific perspective.

Besides, modem over GPRS is always emulated anyway because it is all kept in digital format -- so not a real modem anyway -- but a virtual PC modem (for PC-to-Internet use) over a different kind of a modem (the RIM modem)