the breaking of camp and the leg of travel it begins: a setting out, a stage of a journey
This word comes straight out of tent life. The verb behind it (נָסַע) means to pull up the stakes that hold a tent to the ground, and the noun names what that produces: a camp coming apart and a people on the move. So it is never travel in the abstract. It assumes tents, a place just left, and a place still to be pitched.
Two shades run through its uses. Sometimes it names the moment of departure itself, as when silver trumpets are blown "for the setting out of the camps" and the tribes pull away in their appointed order. Sometimes it names the leg of travel that the departure begins, one measured move from one campsite to the next, which is why Moses can write down a numbered list of them.
That second use gives the wilderness years their shape. The cloud lifts, the stakes come up, the people walk, the stakes go back down, and forty years are recorded as a chain of short moves rather than one long march. Even Abraham's travel through the southern desert is described this way, going "by his stages", the picture of a man who lives in tents rather than a man on a road.
A road word such as דֶּרֶךְ looks at the route being taken, and a distance word such as מַהֲלָךְ measures how far there is to walk. This word looks somewhere else entirely: at the camp being taken down and set up again.