'heatwave' originates from the English words 'heat' and 'wave', where 'heat' meant 'high temperature' and 'wave' referred to a 'period or spell'.

'heatwave' was formed by combining the words 'heat' and 'wave' in the early 20th century to describe a period of hot weather.

Initially, it meant 'a period of hot weather', and this meaning has largely remained the same in modern usage.