How should I pronounce the following things? (These are complexities of algorithms.)

  • O(n)
  • O(n*log(n))
  • O(n^2)
  • 1
    This question is more appropriate for math.stackexchange.com or cstheory.stackexchange.com.
    – Mitch
    Jun 1, 2011 at 16:28
  • 2
    @Mitch cstheory is for research level questions only, see cstheory.stackexchange.com/faq
    – Christi
    Jun 2, 2011 at 18:25
  • I think this is a pointless question. Does OP really want to know whether O is pronounced as Owe rather than Big Oh? Or maybe it should be pronounced zer-OWE? I'm voting to close, and if I could delete it I would do that. Jun 23, 2011 at 3:06

4 Answers 4


Pronunciation would be:

  • order n
  • order n log n
  • order n squared
  • 7
    If the context (of computational order) is already established, I've also heard "o of n" (etc). Jun 1, 2011 at 16:38
  • 1
    Its just known as the 'Big O' in my discrete math class. aka the maximum amount of times an algorithm will be run. Jun 23, 2011 at 2:56

In the talks I've seen that involve algorithm complexity, I've heard it most often pronounced "oh of n", "oh of n log n", etc.

Mathematicians and CS theorists also use a lowercase o and a capital ϴ for similar measurements with slightly different implications. In this case O( n ) would be pronounced "big oh of n", o( n ) "little oh of n", and ϴ(n) "theta of n".


That is commonly referred to as Big O Notation, and since my days as a math/CS student I have always pronounced it (and heard it pronounced) as "Big O of n", "Big O of n log n", etc.


I think it's also common to just say "oh" followed by whatever is inside the parentheses.


There is an "oh n log n" algorithm for that problem

Doesn't that require "oh n squared" time in the worst case?

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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