"multi-vehicle crash," 1929, from verbal phrase pile up "to heap up" (c. 1400), which is attested from 1849 as "to accumulate," 1899 as "to wreck in a heap" (see pile (v.)).
Entries linking to pile-up
pile v.
"to heap (up), lay or throw in a heap," c. 1400, from pile (n.1). Related: Piled; piling. Figurative verbal phrase pile on "attack vigorously, attack en masse," is attested by 1894, American English. To pile in "climb or go on or into in a crowd" is by 1841; hence, for the reverse process, pile out, by 1896.