1. a person who believes in or advocates atomism, the theory that all matter consists of tiny indivisible particles
Usage: philosophy; science

Examples

• The ancient Greek philosopher Democritus was one of the earliest atomists.
• Modern atomists built upon the work of earlier thinkers like Leucippus.
• As an atomist, she believed that everything in nature could be explained by the motion of atoms.
• The atomist theory revolutionized our understanding of matter.
• Many 17th-century scientists were atomists who rejected older theories of matter.
• The atomist view contrasted sharply with the continuous matter theories of the time.