(mathematics) A necessary and sufficient criterion to determine whether a Hermitian matrix is positive-definite: specifically, when all of the leading principal minors have a positive determinant.

(mathematics) A particular statement about the positivity of a certain sequence that is equivalent to the Riemann hypothesis.

(physics) A necessary, but not sufficient, condition for the achievement of sustained release of energy from a nuclear fusion reactor; that the heating effect of the reaction should exceed the losses.

A criterion used by urban planners and architects to assess how comfortable the wind around buildings is for pedestrians (a wind comfort assessment). Commonly used in urban planning in the United Kingdom.

(philosophy) Without criteria or the use of criteria; undiscerning, arbitrary.

Absence of criteria.