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Noun: o
  1. The 15th letter of the Roman alphabet
    - O
Noun: O  ow
  1. The blood group whose red cells carry neither the A nor B antigens
    "people with type O blood are universal donors";
    - type O, group O
  2. A nonmetallic bivalent element that is normally a colourless, odourless, tasteless, nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust
    - oxygen, atomic number 8
Interjection: O  ow
  1. Used to express surprise
    "O, it was only a dollar last time I was here!";
    - Christ, Christmas, crikey [Brit], cripes, cor [Brit], crumbs [Brit], gosh, golly, by George, by Jove, blimey [Brit], gorblimey [Brit], cor blimey [Brit], my, holy cow, holy mackerel, holy smoke, holy moley, holy moly, fancy [Brit], good grief, goodness, goodness me, Gordon Bennett, gracious, gracious me, fancy that, gawd, god, my word, oh, ah, oh boy, jeez, geez, strewth [Brit], struth [Brit], yikes, I'll be blowed [Brit], blow me [Brit], Holy-dooly [Austral], heck, blooming heck [Brit], jeepers, jeepers creepers, Lord, Lordy, marry [archaic], well I never, heavens, good heavens, my goodness, Jesus, bejesus [N. Amer], od [archaic]

Derived forms: Os, os

Type of: alphabetic character, blood group, blood type, chemical element, element, gas, letter, letter of the alphabet

Part of: air, H2O, Latin alphabet, ozone, Roman alphabet, water

Encyclopedia: O, What a Beautiful Mornin'