(cinematography) The phase of film production during which the film is actually shot, as distinct from pre-production and post-production.

plural of vice-principal

An assistant principal or deputy headteacher.

(mathematics) An ultrafilter such that every set belonging to it is the superset of some fixed singleton set.

(algebra) An ideal I in an algebraic object R (which could be a ring, algebra, semigroup or lattice) that is generated by a given single element a ∈ R; the smallest ideal that contains a.

plural of principal investigator

(sciences) lead researcher on a grant-funded project

(mathematics) A complex number which, when raised to the power of n, yields the radicand of its nth degree radical, and which has the greatest real part among all such numbers, and positive imaginary part in case of equality of the real parts.

plural of principal root

(computer security) An entity capable of being authenticated by a computer system or network.