Where does “-oan” come from?

-oan (English) comes from English -ous, from Middle English -ous, from Old French -us, from Latin -ōsus, from Old Latin -ōssus.

-oan (English): Used to convert the name of an atom or ion to an adjective that means containing cations or anions of that atom or ion

Definitions

Used to convert the name of an atom or ion to an adjective that means containing cations or anions of that atom or ion

Step	Language	Word	Meaning
1	English	-ous	Used to form adjectives from nouns, to denote...
2	Middle English	-ous	—
3	Old French	-us	-ous, used for forming adjectives
4	Latin	-ōsus	ose, -ous, -ful (full of or overly prone to)
5	Old Latin	-ōssus	—