What is "haloform reaction"

n. (context chemistry English) the reaction of a halogen with a methyl-ketone to form a haloform

The haloform reaction is a chemical reaction where a haloform (CHX, where X is a halogen) is produced by the exhaustive halogenation of a methyl ketone (a molecule containing the R–CO–CH group) in the presence of a base. R may be alkyl or aryl. The reaction can be used to produce chloroform (CHCl), bromoform (CHBr), or iodoform (CHI).