"action of making hot," late 14c., verbal noun from heat (v.).
Entries linking to heating
heat v.
Old English hætan "to make hot; to become hot," from Proto-Germanic *haita- (see heat (n.)). Related: Heated (with many variants in Middle English); heating. Bartlett ("Dictionary of Americanisms," 1848) reports that het, as past tense and past participle of heat, is "Often heard in the mouths of illiterate people." Compare Middle Dutch heeten, Dutch heten, German heizen "to heat."