formaldehyde

American  

[fawr-mal-duh-hahyd, fer-] / fɔrˈmæl dəˌhaɪd, fər- /

noun

Chemistry.

1. a colorless, toxic, potentially carcinogenic, water-soluble gas, CH 2 O, having a suffocating odor, usually derived from methyl alcohol by oxidation: used chiefly in aqueous solution, as a disinfectant and preservative, and in the manufacture of various resins and plastics.

---

formaldehyde British  

/ fɔːˈmældɪˌhaɪd /

noun

1. Systematic name: methanal.  a colourless poisonous irritating gas with a pungent characteristic odour, made by the oxidation of methanol and used as formalin and in the manufacture of synthetic resins. Formula: HCHO

---

formaldehyde Scientific  

/ fôr-măl′də-hīd′ /

1. A colorless gas having a sharp, suffocating odor. It is used in making plastics and, when dissolved in a solution of water and methanol, to preserve biological specimens. Chemical formula: CH ₂ O.

---

Etymology

Origin of formaldehyde

1870–75; form(ic) + aldehyde; modeled on German Formaldehyd

Compare meaning

How does formaldehyde compare to similar and commonly confused words? Explore the most common comparisons:

• paraformaldehyde vs. formaldehyde

Explanation

No, formaldehyde is not a formal hiding place. Formaldehyde is a strong-smelling colorless gas. Depending on what other elements are combined with it, formaldehyde is used for embalming, manufacturing, and all kinds of other things. Formaldehyde is really good at helping things stick together, which is why it's often used in making things like particleboard and some insulation materials found in buildings. It’s also found in some glues and paints. Besides helping things stick, formaldehyde is famous in science labs for preserving biological specimens, like animals and plants, so that they can be studied without decaying.

Example Sentences

Preserved in formaldehyde and paraffin wax, they come from patients treated at the UK's national bowel hospital, St Mark's, in northwest London.

From Barron's • Feb. 4, 2026

Others include multiple types of exposures associated with fume events: chemicals that appear in both pesticides and engine oils; high levels of ultrafine particles and solvents like formaldehyde; and brain trauma.

From The Wall Street Journal • Dec. 22, 2025

He also raised safety and health concerns when Alameda Health System changed how Highland Hospital disposed of formaldehyde.

From Los Angeles Times • Apr. 16, 2025

Non-biodegradable coffins are often made with harmful chemicals and bodies are embalmed using formaldehyde: a toxic substance which can leach into soil.

From BBC • Dec. 14, 2024

“Only, you know, without the formaldehyde smell this time.”

From "Far from the Tree" by Robin Benway

Related Words

• vinegar