diatom

noun

di·​a·​tom ˈdī-ə-ˌtäm 

: any of a class (Bacillariophyceae) of minute planktonic unicellular or colonial algae with silicified skeletons that form diatomaceous earth

Examples of diatom in a Sentence

Recent Examples on the Web

For example, diatoms have a competitive advantage over small phytoplankton under iron-rich conditions in the Southern Ocean. —Ashley Strickland, CNN, 5 Feb. 2025

Some, such as diatoms, can consume dissolved organic nutrients directly from the water. —Quanta Magazine, 29 Jan. 2025

Over time, algae and diatoms flourish, forming a richer food base that rejuvenates the pupfish population. —Scott Travers, Forbes, 29 Nov. 2024

This natural powder is made from fossilized remains of diatoms, a type of hard-shelled algae. —Nafeesah Allen, Better Homes & Gardens, 22 Sep. 2024

Word History

Etymology

ultimately from Greek diatomos cut in half, from diatemnein to cut through, from dia- + temnein to cut — more at tome

First Known Use

1845, in the meaning defined above

Kids Definition

diatom

noun

di·​a·​tom ˈdī-ə-ˌtäm 

: any of a class of minute floating single-celled or colonial algae that are common in fresh and salt water and have a cell wall of silica that remains as a skeleton after death

diatomaceous

ˌdī-ət-ə-ˈmā-shəs

adjective

Medical Definition

diatom

noun

di·​a·​tom ˈdī-ə-ˌtäm 

: any of a class (Bacillariophyceae) of minute planktonic unicellular or colonial algae with silicified skeletons that form diatomite