1. One who, or that which, dives. Divers and fishers for pearls. (Woodward)
2. One who goes deeply into a subject, study, or business. A diver into causes.
3. (Science: zoology) Any bird of certain genera, as Urinator (formerly Colymbus), or the allied genus Colymbus, or Podiceps, remarkable for their agility in diving.
The northern diver (Urinator imber) is the loon; the black diver or velvet scoter (Oidemia fusca) is a sea duck. See loon, and scoter.