Word.ws English Dictionary

o-

o- noun: a blood type that has no antigens. It lacks the A, B and Rh factors on the blood cells. It is the universal donor for blood and can give blood to any blood type, but can only receive O- blood.

Noun

o-

  1. A blood type that has no antigens. It lacks the A, B and Rh factors on the blood cells. It is the universal donor for blood and can give blood to any blood type, but can only receive O- blood.

Prefix

o-

  1. ortho-

Questions about o-

What does o- mean?
O- means a blood type that has no antigens. It lacks the A, B and Rh factors on the blood cells. It is the universal donor for blood and can give blood to any blood type, but can only receive O- blood.
What part of speech is o-?
O- can be a noun or a prefix.

Words near o- in the dictionary

  1. O'Toole
  2. O'Ward
  3. O'Wards
  4. O'Yeung
  5. O'Young
  6. o-
  7. O-1
  8. O-1A
  9. O-1As
  10. O-1B
  11. O-1Bs

Source and license

Adapted from Wiktionary: o- (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

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Cite this entry: “o-.” Word.ws, https://word.ws/o-. Based on Wiktionary, CC BY-SA 4.0.