This is the 5457th most frequent Spanish word.
olas
Waves.
'Olas' is used figuratively here to describe intense episodes of weather conditions, specifically heat in this case.
Las olas de calor son comunes en el verano.
Heat waves are common in the summer.
Here, 'olas' is used to describe the natural waves found in the sea or ocean.
Las olas del mar son muy altas hoy.
The waves of the sea are very high today.
In this sentence, 'olas' metaphorically describes the motion of waving a hand.