(number theory, recreational mathematics) A magic square that remains magic even if all its numbers are replaced by their kth powers for 1 ≤ k ≤ P.

plural of betweenness

(optics) Describes the optics of a beam splitter

(politics) An amendment made in bad faith by a legislator who disagrees with the principles of a bill and seeks to make it useless rather than simply voting against it.