A series of thoughts or actions which feeds back into itself, causing a situation to become progressively worse. It is worse than a vicious circle, which is self-sustaining in its current state.

(sports) A long pass in American football or rugby in which the ball is given a brisk spin (about its longitudinal axis) as it is thrown so that it travels in a smooth arc without tumbling or wobbling.

plural of spiral pass

plural of Ulam spiral

(mathematics) A graphical depiction of the set of prime numbers, constructed by writing the positive integers in a square spiral and specially marking the primes.

(astronomy) Ellipsis of superluminous spiral galaxy.

plural of arithmetic spiral

plural of spiral galaxy

(astronomy) A section of a spiral galaxy that coils out from the centre.

plural of spiral arm