English Language & Usage Stack Exchange is a question and answer site for linguists, etymologists, and serious English language enthusiasts. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I was wondering if there are differences between the cases of using di- and the cases of using bi-?

For example,

  • why carbon dioxide instead of carbon bioxide?
  • Why binoculars instead of dinoculars?
  • Why bisexual instead of disexual?
  • Why bilateral instead of dilateral?
share|improve this question
Almost 2k points and you're still saying "thanks" in a post? – simchona Feb 9 '12 at 21:15
Don't say "thanks" in a post. It's spam. – simchona Feb 9 '12 at 21:16
@MattЭллен: What if I don't buy that? – Tim Feb 9 '12 at 21:55
up vote 11 down vote accepted

Bi- comes from Latin, Di- from Greek. Which prefix is used would usually depend on the origin of the root of the word.

share|improve this answer
Thanks! Seems like I have to learn history of each such word! Possibly any rule saying that which is used more often in what category? For example, in chemistry, di-; in social science and physics, bi-? – Tim Feb 9 '12 at 21:18
Precisely. Dioxide is a Greek word, whereas binoculars and bisexual are of Latin origin. +1. – Irene Feb 9 '12 at 21:20
You could learn the history ... or you could just accept whatever you find in the dictionary. While it is sometimes useful to know the origins of a word, 95% of the time you can just use it without having to know that it came from Latin via French or that it was coined by Hiram Slocum in 1892 or whatever. – Jay Feb 9 '12 at 22:02
Plenty of Latin words have the prefix di- or dis- thought they often lose the sense of 2 by the time they arrive in English: compare bisection and dissection. – Henry Feb 9 '12 at 22:51
@Henry: In mathematics, is bi- more often than di-? I cannot think of some examples with di-. – Tim Feb 9 '12 at 23:11

protected by RegDwigнt Mar 14 '13 at 11:58

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.