Definitions
1.NounA curve that is the locus of a point that rotates about a fixed point while continuously increasing its distance from that point.
2.NounA helix.
3.NounA self-sustaining process with a lot of momentum involved, so it is difficult to accelerate or stop it at once.
4.NounA section of track that forms a circle and crosses over itself, used for gaining height in mountainous territory.
5.AdjectiveHelical, like a spiral.
6.VerbTo move along the path of a spiral or helix."The falling leaves spiralled down from the tree."
7.VerbTo cause something to spiral."You need to learn how to spiral a ball."
8.VerbTo increase continually."Her debts were spiralling out of control."
9.VerbTo decline mentally."She spiralled into a deep depression."