A gorge is a very deep crevice between two mountains or hills. Gorges are formed by rivers running through and eroding rock over a very long period of time.
The Latin root of gorge means "throat," leading to both the "narrow passage" meaning and the French gorgier, "to swallow," which influenced the verb version of gorge, "to overeat." You may love to gorge on ice cream, but the stomachache afterword won't be very pleasant. To remember the "canyon" meaning, think of the famous upstate New York bumper sticker, “Ithaca is gorges.” It's a play on gorgeous, meaning beautiful, and the beautiful ravines in the area.