pile up

verb piles up · piling up · piled up

1. transitive To form a pile, stack, or heap. The kids piled up their boots and coats by the back door.
2. idiomatic, intransitive To collect or accumulate, as a backlog. The requests piled up while she was away.
3. intransitive To sustain a motor vehicle accident; to crash. Nevertheless, if there were no urgent reason for it, I did not fancy driving anything, much less a large, heavily loaded truck, by night along roads which might reasonably be expected to produce a number of hazards. If I were to pile it up, and the odds were that I should, I would lose a lot more ti