(CELLular telePHONE) The first ubiquitous wireless telephone. Originally analog, all new cellular systems are digital, which has enabled the cellphone to turn into a handheld personal computer (see smartphone).

Introduced in the mid-1980s, cellphone sales exploded worldwide in the 1990s. By 2008, there were more than three billion in use, and many users have become addicted (see nomophobia). A cellphone is also called a "mobile phone" or "mobile," especially outside the U.S.

Major Carriers
In the U.S., the major cellular carriers are AT&T (formerly Cingular), Verizon Wireless (formerly Bell Atlantic Mobile and Alltel), Sprint Nextel (merger of Sprint and Nextel), T-Mobile and Virgin Mobile USA. The largest cellular company in the world is UK-based Vodafone, which includes substantial ownership in Verizon Wireless.

Cell Technology
Geographic areas are divided into a number of slightly overlapping circular "cells." Each cell contains a base station, which is identifiable by its transmitting and receiving antenna located on a tower at the top of a hill or building. The base stations connect to the landline telephone system of the country.

The multiple cells combined with low power transmitters allow the same frequencies to be reused with different conversations in different cells within the same city or locale. The primary digital cellphone technologies are TDMA, CDMA and GSM. See 3G, PCS, AMPS, GSM, TDMA, CDMA, WAP, cellspace, screaming cellphone and cordless phone.