(geometry) A curve that is the locus of a point that rotates about a fixed point while continuously increasing its distance from that point.

(informal) A helix.

A self-sustaining process with a lot of momentum involved, so it is difficult to accelerate or stop it at once.

(rail transport) A section of track that forms a circle and crosses over itself, used for gaining height in mountainous territory.

(intransitive) To move along the path of a spiral or helix.

(transitive) To cause something to spiral.

(figurative, intransitive) To increase continually.

Helical, like a spiral.