- a seabird related to the shearwaters, typically flying far from land.
- Order Procellariiformes, in particular the families Procellariidae (e.g., the giant petrel and pintado petrel) or Hydrobatidae (the storm petrels). See also diving petrel
early 17th century: associated with St. Peter, from the bird's habit of flying low with legs dangling, giving the appearance of walking on the water (see Matt. 14:30)