Final answer:
A tooth is secured by fibrous periodontal ligaments and the joint type is known as a synarthrosis, specifically called a gomphosis.
Step-by-step explanation:
A tooth is held firmly in place by fibrous periodontal ligaments. This joint is functionally classified as a synarthrosis. A gomphosis is the specific type of fibrous joint that anchors the root of a tooth into its bony socket in the jaw. Due to the immobility of a gomphosis, it is considered a synarthrosis, which is a type of joint that allows for little to no movement between the bones it connects.