formaldehyde

noun

form·​al·​de·​hyde fȯr-ˈmal-də-ˌhīd 

fər-

: a colorless pungent irritating gas CH₂O used chiefly in aqueous solution as a disinfectant and preservative and in chemical synthesis

Examples of formaldehyde in a Sentence

Recent Examples on the Web

Her brain should be kept in formaldehyde and studied by scientists in the future as a specimen of Realitus televisus. —Rafaela Bassili, Vulture, 27 Jan. 2026

The New Standard Institute said this disposable clothing has been found to contain hazardous substances such as lead, formaldehyde and phthalates, which have been linked to serious health issues and contamination of waterways. —Jennifer Bringle, Sourcing Journal, 16 Jan. 2026

Multiple studies have shown that burning methane gas produces nitrogen oxide, carbon monoxide, formaldehyde and benzene that can worsen respiratory illnesses such as asthma and increase the risk of cancer. —Alan K. Chen, The Conversation, 18 Dec. 2025

Come for the 21-free formula absent of potentially harmful ingredients like formaldehyde, camphor, and DHP; stay for the incredibly smooth application. —Taryn Brooke, Glamour, 16 Dec. 2025

Word History

Etymology

International Scientific Vocabulary form- + aldehyde

First Known Use

1872, in the meaning defined above

Phrases Containing formaldehyde

• urea-formaldehyde

Rhymes for formaldehyde

• acetamide
• acetonide
• acidified
• antimonide
• beatified
• benzaldehyde
• borohydride
• chalcogenide
• commodified
• decalcified
• declassified
• disaccharide

Kids Definition

formaldehyde

noun

form·​al·​de·​hyde fȯr-ˈmal-də-ˌhīd 

fər-

: a colorless gas that consists of carbon, hydrogen, and oxygen, has a sharp irritating odor, and when dissolved in water is used to disinfect or to prevent decay

Medical Definition

formaldehyde

noun

form·​al·​de·​hyde fȯr-ˈmal-də-ˌhīd, fər- 

: a colorless pungent irritating gas CH₂O used chiefly as a disinfectant and preservative and in chemical synthesis