INION

inion

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

Source: WordNet® 3.1

Etymology

Noun

inion (plural inia or inions)

(anatomy) A small protuberance on the external surface of the back of the skull near the neck; the external occipital protuberance.

Source: Wiktionary

In"i*on, n. Etym: [NL., fr. Gr. 'ini`on the back of the head.] (Anat.)

Definition: The external occipital protuberance of the skull.

Source: Webster’s Unabridged Dictionary 1913 Edition