(geometry, topology, mathematical analysis) A version of winding number in which the number of rotations is counted with respect to the tangent of the curve rather than a fixed point.

An identification number assigned to a particular quantity or lot of material from a single manufacturer.

(Christianity) Number of the Beast

(physics) The ratio between mean free path and aperture size used as a parameter in describing Knudsen flow.

Synonym of split-complex number

(number theory) An algebraic integer that represents an ideal in the ring of integers of a number field.

(mathematics, chiefly historical) Synonym of pi, particularly the 35-decimal approximation discovered by Ludolph van Ceulen

(mathematics) For a given number n, the number of different ways of drawing non-intersecting chords between n points on a circle (not necessarily touching every point by a chord). They have diverse applications in geometry, combinatorics, and number theory.

(mathematics) The number of possible paths from the southwest corner (0, 0) of a rectangular grid to the northeast corner (m, n), using only single steps north, northeast, or east.

(mathematics) The number of possible lattice paths from the southwest corner (0, 0) of an n × n grid to the northeast corner (n, n), using only single steps north, northeast or east, and not rising above the southwest–northeast diagonal.