Multiple rounds or divisions of a race or competition, or plural of heat meaning high temperature or intense energy.
Old English 'hæt,' related to Germanic languages. In sports, 'heat' became the term for a preliminary round in the 1800s, likely from the idea of warming up or building intensity before the final.
Interestingly, 'heat' in racing originally came from livestock breeding—animals 'in heat' are ready to reproduce, and racers adopted the word to describe preliminary rounds that 'warmed up' competitors before the main event.
Complete word intelligence in one call. Free tier — 50 lookups/day.