paraformaldehyde
/ˌparəfɔːˈmaldɪhʌɪd/ /ˌparəfəˈmaldɪhʌɪd/Chemistry
noun
A white crystalline solid, obtained by the evaporation of an aqueous solution of formaldehyde (methanal), which is a polymer of formaldehyde and is used as a disinfectant, fumigant, and bactericide, and as an intermediate in chemical synthesis; polyoxymethylene, (HCHO)n.
Origin
Late 19th century; earliest use found in Journal of the Chemical Society. From para- + formaldehyde.