A mobile phone or cell phone is a portable telephone that can make and receive calls over a radio frequency link while the user is moving within a telephone service area, as opposed to a fixed-location phone. The radio frequency link establishes a connection to the switching systems of a mobile phone operator, which provides access to the public switched telephone network (PSTN). Modern mobile telephone services use a cellular network architecture, and therefore mobile telephones are called cellphones in North America. In addition to telephony, digital mobile phones support a variety of other services, such as text messaging, multimedia messaging, email, Internet access, short-range wireless communications, satellite access, business applications, payments, multimedia playback and streaming, digital photography, and video games. Mobile phones offering only basic capabilities are known as feature phones ; mobile phones that offer greatly advanced computing capabilities are referred to as smartphones.

भ्रमणध्वनी हे एक इलेक्ट्रॉनिक्स उपकरण (यंत्र) असून याचा दूरसंचारासाठी उपयोग केला जातो. याला इंग्रजीमध्ये मोबाईल फोन (मोबाईल) किंवा सेल्युलर फोन असे म्हणतात. भ्रमणध्वनीच्या साहाय्याने संभाषणाची व माहितीची देवाणघेवाण करता येते. आज भ्रमणध्वनी माणसाच्या जीवनाचा एक महत्वाचा भाग बनलेला आहे. पारंपरिक दूरध्वनी उपकरणे घरामध्ये एकाच जागी ठेवून वापरावी लागतात.