Odd may mean:

• In everyday language: the quality of being unpaired, occasional, strange or unusual, or a person who is viewed as eccentric
• In mathematics:
  • an integer is odd if dividing it by two does not result in another integer; see even and odd numbers
  • a function f defined on the real numbers is odd if f(x) = −f(−x) for all x; see even and odd functions
  • a permutation of a finite set is odd if it can be written as the functional composition of an odd number of transpositions; see even and odd permutations
  • In probability theory, the odds in favour of an event is the ratio of the event's probability to the complementary probability.
• Odd (name), is a name of Old Norse origin, the 11th most common male name in Norway (coincidentally, Even is also a common Norwegian name). In Old Norse the word means the sharp end of a weapon, e.g. edge of a sword or spear/arrow head.
• Odd, West Virginia, USA
• Odd Grenland B.K., is a Norwegian football team
• Odd Della Robbia, a character in Code Lyoko

ODD may mean:

• Optical disc drive (CD/DVD/Blu-ray Disc/HD-DVD Drive)
• Oppositional defiant disorder
• ODD (fanzine), a Hugo-nominated science fiction fanzine published by Raymond "Duggie" Fisher
• In computer science, ODD (One Document Does it all) is a W3C specification
• ODD, a play by Hal Corley.