Cellular means made up of or relating to cells, the tiny building blocks that make up all living things. Your body contains trillions of cells working together: muscle cells that help you move, brain cells that help you think, and skin cells that protect you from the outside world. Each cell is like a microscopic factory with its own job to do.

When scientists look at a leaf under a microscope, they see its cellular structure: thousands of plant cells packed together like bricks in a wall. The word cellular helps us talk about how living things are organized at their most basic level. A cellular organism is any living thing made of cells, from a single-celled bacterium to a blue whale with quadrillions of cells.

The word also describes things that work like cells do, divided into small units. A cellular blanket has a pattern of small, connected spaces like a honeycomb. Cellular phones (or cell phones) got their name because they work through a network divided into small areas called cells, each with its own tower. When you move around with your phone, it switches from cell to cell to stay connected.