The Greek translators of the Hebrew Bible needed a word for an offering that was burned in its entirety, and they built one: holokautoma and its relatives, from holos, whole, and kaustos, burned. The Latin translators took it over as holocaustum. In English it arrives by way of French as holocaust, and for several centuries it meant what it says, a sacrifice consumed by fire, and nothing else. It was still being used that way in the seventeenth century of the offerings of Leviticus.
The extension of the word to mass slaughter by fire is much later, and its application to the murder of European Jews became fixed only after the Second World War. That the term now names the destruction of a people and once named an offering brought by that people is an accident of translation history rather than a connection anybody intended, and it is the reason the Hebrew word Shoah is often preferred. The atlas records the etymology because the descent is real and traceable, not because the two senses illuminate one another.
The Hebrew is more literal and less dramatic. Olah is a participle of the verb to go up. The ascent it names may be the animal's, taken up onto the raised altar, or the smoke's, and the sources do not settle which. The other name that appears in the text, kalil, means simply entire. Neither carries the sense of destruction that the Greek word acquired, which is worth holding onto when reading the class: what the tradition emphasises about the olah is that all of it is given, not that all of it is destroyed.