Cellular refers to the mobile network system that lets devices such as smartphones connect to voice and data services without wires. The coverage area is divided into many small regions called cells, each served by its own radio mast or base station. When you make a call or browse the internet, your device links to the nearest tower, and as you move from one cell to another the connection is seamlessly passed on so you stay online.
Over time cellular technology has evolved from basic voice calls in 2G, to fast mobile broadband in 4G and ultra-low latency data in 5G, with each evolution offering greater capacity, speed and reliability. Mobile operators allocate radio frequencies to each cell, manage those frequencies to avoid interference and coordinate handovers between towers to ensure continuous service across towns, cities and rural areas.