acervation
/ˌasəːˈveɪʃn/noun
The action of forming something into a mass or of piling something up in a heap or heaps; accumulation.
Origin
Early 17th century; earliest use found in Thomas Lodge (1558–1625), author and physician. From classical Latin acervātiōn-, acervātiō action of heaping up or piling together, accumulation from acervāt-, past participial stem of acervāre + -iō.