D defs.my
Entry 1 sense Webster, 1913

Heating

/(hēt"ĭng)/ · Heat·ing · IPA /ˈhiːtɪŋ/
01 a. That heats or imparts heat; promoting warmth or heat; exciting action; stimulating; as, heating medicines or applications.
  1. 1.
    That heats or imparts heat; promoting warmth or heat; exciting action; stimulating; as, heating medicines or applications.
Phrases & compounds
Heating surface — the aggregate surface exposed to fire or to the heated products of combustion, esp. of all the plates or sheets that are exposed to water on their opposite surfaces; -- called also fire surface.