Inion and Noggin

Inion noun - The craniometric point that is the most prominent point at the back of the head (at the occipital protuberance).

Noggin and inion are semantically related. In some cases you can use "Noggin" instead a noun "Inion".

Noggin noun - The upper or front part of the body that contains the brain, the major sense organs, and the mouth.

Inion and noggin are semantically related. Sometimes you can replace term "Inion" with "Noggin", this nouns are similar.