What is "circle of the gorge"

Gorge \Gorge\, n. [F. gorge, LL. gorgia, throat, narrow pass, and gorga abyss, whirlpool, prob. fr. L. gurgea whirlpool, gulf, abyss; cf. Skr. gargara whirlpool, g[.r] to devour. Cf. Gorget.]

1. The throat; the gullet; the canal by which food passes to the stomach.

   Wherewith he gripped her gorge with so great pain.
   --Spenser.

   Now, how abhorred! . . . my gorge rises at it.
   --Shak.

2. A narrow passage or entrance; as:

   1. A defile between mountains.

   2. The entrance into a bastion or other outwork of a fort; -- usually synonymous with rear. See Illust. of Bastion.

3. That which is gorged or swallowed, especially by a hawk or other fowl.

   And all the way, most like a brutish beast, e spewed up his gorge, that all did him detest.
   --Spenser.

4. A filling or choking of a passage or channel by an obstruction; as, an ice gorge in a river.

5. (Arch.) A concave molding; a cavetto.
   --Gwilt.

6. (Naut.) The groove of a pulley.

7. (Angling) A primitive device used instead of a fishhook, consisting of an object easy to be swallowed but difficult to be ejected or loosened, as a piece of bone or stone pointed at each end and attached in the middle to a line.

   Gorge circle (Gearing), the outline of the smallest cross section of a hyperboloid of revolution.

   Circle of the gorge (Math.), a minimum circle on a surface of revolution, cut out by a plane perpendicular to the axis.

   Gorge fishing, trolling with a dead bait on a double hook which the fish is given time to swallow, or gorge.

   Gorge hook, two fishhooks, separated by a piece of lead.
   --Knight.