Definition of diazomethane in English:
 diazomethane
noun dʌɪˌazəʊˈmiːθeɪndʌɪˌeɪzəʊˈmiːθeɪndīˌazōˈmeTHān
mass nounChemistry A poisonous, reactive yellow gas used as a methylating agent in chemical synthesis.
Chemical formula: CH₂N₂
 Example sentencesExamples
-  Caution: the reaction sequence should be carried out behind a blast shield and in the hood because diazomethane is a vapor.
 -  Samples were evaporated to dryness under vacuum, redissolved in 20 mm of methanol, then diazomethane added to methylate ABA.
 -  Lipids were extracted according to the method of Bligh and Dyer, followed by methylation with ethereal diazomethane.
 -  With diazomethane itself, you can watch its color disappear and know that something's happening.
 -  The sap samples were thawed and an internal standard of [H 6] ABA was added before they were dried, methylated with ethereal diazomethane, dried and redissolved in methanol for analysis by gc/ms.
 
Origin
  
Late 19th century: from diazo- (indicating the presence of two nitrogen atoms) + methane.