Initialism of New Zealand Property Investors' Federation.

The study of error in mathematical approximations.

(mathematics) An abstraction of distance; a function, d, with two arguments that satisfies d(x,x) = 0 and d(x, y) + d(y,z) ≥ d(x,z) (the triangle inequality) for all x,y,z in the domain.

In a magisterial manner; authoritatively.