means A passage is a way through — a corridor, channel, or route — or a stretch of text or music carved out as its own moving section.

from From Old French 'passage,' built on 'passer,' to pass, which traces back to Latin 'passus,' a step or pace — literally the spread of the legs in walking. So a passage was first a passing, an act of going through; only later did it harden into the thing you pass through. The textual sense — a 'passage' in a book — borrows the same image: a place the reading eye travels across.