diver

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. One that dives: a high diver who excelled in performing the jackknife.
2. n. One that works under water, especially one equipped with breathing apparatus and weighted clothing.
3. n. Any of several diving water birds, especially the loon.

Century Dictionary and Cyclopedia

1. n. One who or that which dives or plunges into water.
2. n. Specifically— One who makes a business of diving, as for pearl-oysters, to examine sunken vessels, etc. See submarine armor, under armor.
3. n. A bird that habitually dives, as a loon, grebe, auk, or penguin; specifically, one or any of the birds variously known as Brachypterœ, Mergitores, Urinatores, Pygopodes, or Spheniscomorphœ. The term is especially applied to the loons, family Colymbidœ (which see). There are three leading species: the great northern diver, Colymbus torquatus; the black-throated diver, C. arcticus; and the red-throated diver, C. septentrionalis. All three inhabit the northern hemisphere generally, and are noted not only for their quickness in diving, but also for the length of time they remain and the distance they traverse under water, in which they move both by swimming with the feet and by paddling with the wings. See loon. Also diving-bird.
4. n. One who plunges into or engages deeply in anything.
5. n. See dyvour.

Wiktionary

1. n. someone who dives, especially as a sport
2. n. someone who works underwater; a frogman
3. n. the loon (bird)
4. n. The New Zealand sand diver
5. n. The Long-finned sand diver
6. n. brother-in-law (one's husband's brother)

GNU Webster's 1913

1. n. One who, or that which, dives.
2. n. Fig.: One who goes deeply into a subject, study, or business.
3. n. Any bird of certain genera, as Urinator (formerly Colymbus), or the allied genus Colymbus, or Podiceps, remarkable for their agility in diving.

WordNet 3.0

1. n. someone who dives (into water)
2. n. large somewhat primitive fish-eating diving bird of the northern hemisphere having webbed feet placed far back; related to the grebes
3. n. someone who works underwater