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

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

These deposits contain tiny microfossils of plankton, including organisms such as diatoms and coccolithophores that live on or near the ocean’s surface. —Suzanne Oconnell, The Conversation, 3 Sep. 2024

This iceberg is large enough to interfere with the additional primary production (diatoms, like algae) that is produced as the nutrient rich water that upwells in the Taylor column feeds the phytoplankton. —Taylor Nicioli, CNN, 15 Aug. 2024

Inside each diatom were four to eight bacterial cells. —Quanta Magazine, 17 July 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