stack up phrasal verb (
see also stack)
1. stack something ↔ up to make things into a neat pile
2. informal used to talk about how good something is compared with something else
stack up against
Parents want to know how their kids’ schools stack up against others.3. if a number of things stack up, they gradually collect or get stuck in one place:
Traffic stacked up behind the bus. [TahlilGaran] Dictionary of Contemporary English ▲