To change how close a view stands to what it shows. Detail and context trade against each other.
English zoom, imitative in origin — coined in the late 19th century to sound like the hum of a sudden, fast motion (an engine's rush, an airplane's climb) before the word was carried over, in 1930s photography, to the lens that makes a view rush toward or away from its subject.
Distance made adjustable — nothing about the thing itself changes, only how near the frame stands to it and how much of it fits inside that frame. Detail bought with context, or context bought back with detail, one dial at a time.