(1):

(a.) Of or pertaining to a spiral; like a spiral.

(2):

(a.) A plane curve, not reentrant, described by a point, called the generatrix, moving along a straight line according to a mathematical law, while the line is revolving about a fixed point called the pole. Cf. Helix.

(3):

(a.) Winding round a cylinder or imaginary axis, and at the same time rising or advancing forward; winding like the thread of a screw; helical.

(4):

(a.) Anything which has a spiral form, as a spiral shell.

(5):

(a.) Winding or circling round a center or pole and gradually receding from it; as, the spiral curve of a watch spring.