In 1665, British physicist Robert Hooke first used the term “cell” to describe the divisions he observed in a slice of cork. Using a microscope that magnified thirty times, Hooke identified little chambers or compartments in the cork that he called cellulae—a Latin term meaning “little rooms”—because they reminded him of the small monastery cells inhabited by monks. (He further calculated that one square inch [6.45 square centimeters] of cork would contain 1,259,712,000 of these tiny chambers or “cells.”) This word evolved into the modern term “cell.”