pile up

Verb

pile up (third-person singular simple present piles up, present participle piling up, simple past and past participle piled up)

1. (transitive) To form a pile, stack, or heap.
   • The kids piled up their boots and coats by the back door.
   • And still the hours passed, and at last I knew by the glimmer of light in the tomb above that the sun had risen again, and a maddening thirst had hold of me. And then I thought of all the barrels piled up in the vault and of the liquor that they held; and stuck not because 'twas spirit, for I would...[1898], J[ohn] Meade Falkner, Moonfleet, London; Toronto, Ont.: Jonathan Cape, published 1934, →OCLC

   Synonyms:

   accumulate, agglomerate, amass, build up, cumulate, heap, heap up, mound, pile, rack up

2. (idiomatic, intransitive) To collect or accumulate, as a backlog.
   • The requests piled up while she was away.
   • The locomotive was the now inevitable American 2-8-0, No. 2623. There she stood, effectively blocking the level crossing, simmering gently, massively inert. It was almost dark, and one's final sight was of her high, firelit cab, the enginemen nonchalantly leaning out, waiting for the right-away...1945 January and February, “Notes and News: American Locomotives in France”, in Railway Magazine, page 46

   Synonyms:

   head up

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...1951, John Wyndham, The Day of the Triffids, Harmondsworth: Penguin Books, published 1954, page 157
   • Seven cars piled up in a concertina smash on the Pacific Highway this morning about four miles on the Brisbane side of Southport.1953 July 13, The Northern Star, Lismore, page 4, column 3