The numbers 1, 3, 5, and 35 are all odd numbers — they can't be divided by two. They are not even. Also, things that are weird or strange are called odd.
This word covers things that are slightly off-kilter, like odd numbers. You can use odd for a single thing that belongs in a pair, like an odd sock or odd mitten. If someone wants you to do odd jobs, that could mean almost anything: odd jobs are random and unpredictable jobs that could come up. When you describe a person as odd, or that they’re exhibiting odd behavior, it means they're peculiar and out of the ordinary.