Heavy Water 2 : (1) Water deep on the floor due to the large quantity required to extinguish a fire. (2) Water made with heavy isotopes of hydrogen; it is used in nuclear research.
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}