fire extinguisher /ˈfaɪəɹ ɪkˌstɪŋ.ɡwɪʃ.ə(ɹ)/ noun1 •A device that can be used to put out a fire. Usually a portable cylinder filled with carbon dioxide, dry powder or water, in the latter two cases with some means of pressurising the cylinder to expel the contents.Two fire extinguishers are fitted in the kitchen and one above a corner cupboard in the vestibule. — 1960 formsfire extinguishers · fire-extinguishers