The term "cells" was first coined by Robert Hooke in his 1665 book Micrographia. Hooke used the term to describe the small compartments he observed in cork under a microscope. He compared the cells to the cells in a honeycomb, which is why he chose the term "cell."

Hooke's use of the term "cells" was significant because it was the first time that a scientist had used the word to describe the basic unit of life. Hooke's observations laid the foundation for the field of cell biology, which is the study of cells and their functions.