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

A helix.

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

To move along the path of a spiral or helix.

“The falling leaves spiralled down from the tree.”

To cause something to spiral.

“You need to learn how to spiral a ball.”

To increase continually.

“Her debts were spiralling out of control.”

Helical, like a spiral