for‧mal‧de‧hyde /fɔːˈmældəhaɪd, fɔːˈmældɪhaɪd $ fɔːr-/ noun [uncountable]
[Date: 1800-1900; Origin: formic (FORMIC ACID) + aldehyde type of chemical]
a strong-smelling gas that can be mixed with water and used for preserving things such as dead animals to be used in science etc:
frogs preserved in formaldehyde

[TahlilGaran] Dictionary of Contemporary English ▲