A pileup can refer to: Multiple-vehicle collision In nuclear and particle physics, a situation where a particle detector is affected by several events at the same time. In ham radio, particularly in DXing slang, the presence of many ham operators trying to communicate with a distant entity, all in the same time. Pile Up, an album by queercore band Pansy Division Pileup format, a file format used in the field of Bioinformatics