What is a point of contact between two bones, between bone and cartilage, or between bone and teeth called?

The point where two bones, bone and cartilage, or bone and teeth make contact is called a joint. This is usually what allows the body to bend. So, you have a hip joint in your hip bone to allow your legs to move enough that you can walk, run, skip, ride a bike, etc. You have cartilage in your fingers, and three joints in your finger: one by the nail, one in the middle, and one at the palm. This allows you to move your fingers to type, to knit, to craft, to write, etc.

The joints are also a place of pain in later life. Arthritis, for example, is when joints swell to the point that it is difficult and/or painful to move them.