The story
Blend of walking + school bus. Coined by analogy with a conventional school bus.
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A group of students who walk to school chaperoned by two adults (the "driver" leading and the "conductor" following), according to a fixed route with designated "bus stops" where further students can join the group. Full definition →
Blend of walking + school bus. Coined by analogy with a conventional school bus.
Etymology from Wiktionary, CC BY-SA 4.0.