- Date: 14th century
- b : supposition
- b : a conclusion deduced by surmise or guesswork
- c : a proposition (as in mathematics) before it has been proved or disproved
A conjecture is a proposition that is unproven but appears correct and has not been disproven. Karl Popper pioneered the use of the term "conjecture" in philosophy. Conjecture is contrasted by hypothesis (hence theory, axiom, principle), which is a testable statement based on accepted grounds. In mathematics, a conjecture is an unproven proposition or theorem that appears correct.