a pungent gas, HCHO, used in solution as a strong disinfectant and preservative, and in the manufacture of synthetic resins, dyes, etc.
Origin:
form(ic) + aldehyde
See formaldehyde in American Heritage Dictionary 4
noun
A colorless gaseous compound, HCHO, the simplest aldehyde, used for manufacturing melamine and phenolic resins, fertilizers, dyes, and embalming fluids and in aqueous solution as a preservative and disinfectant.