Polyidus (or Polyeidus) was an Argive seer whose advice helped Bellerophon to tame Pegasus. He also foresaw the death of Minos' son Glaucus who was drowned in ajar of honey (see Glaucus). His name means 'many shapes', from polys, 'many' and eidos, 'something seen', 'form', 'shape'. This is an appropriate name for a seer.
