(mathematics) A characteristic of an exponential function, represented by τ in the function:

(calculus) An unspecified constant term added to a particular antiderivative to make it represent its whole family of antiderivatives, usually denoted with C.

(physics) A term added by Albert Einstein to his equations of general relativity in order to account for a supposed static universe, since used to describe vacuum energy as a form of dark energy.

(logic) A word or phrase which has an invariant logical meaning and which is useful for forming argument forms.

(crystallography) The constant distance between unit cells in a crystal lattice. It may be different in each direction, thus a crystalline substance may have up to three lattice constants.

(mathematics) A constant that maintains the same value wherever it occurs; such as π. / Used other than figuratively or idiomatically: see absolute, constant.

(chemistry) A measure of the relative concentrations of the reactants and products of a reversible reaction at equilibrium

(logic) One of a set of letters or symbols which are assigned fixed truth values independently of any interpretation or valuation, and each of which qualifies as a prime formula of their language.

(computing theory) A real number that informally represents the probability that a randomly-constructed program will halt.

(mathematics, chiefly historical) Synonym of pi