Where does “janeiru” come from?

janeiru (Tetum) comes from Portuguese Janeiro, from Old Portuguese janeyro, from Latin iānuārius, from Latin -ārius, from Proto-Italic *-āzios — Forms relational adjectives to nouns (and rarely numerals).

janeiru (Tetum): January

Definitions

January

Ancestry of “janeiru”, step by step

Step	Language	Word	Meaning
1	Portuguese	Janeiro	Superseded spelling of janeiro
2	Old Portuguese	janeyro	January
3	Latin	iānuārius	of January
4	Latin	-ārius	er
5	Proto-Italic	*-āzios	Forms relational adjectives to nouns (and rarely numerals)

Every word from Proto-Italic *-āzios →Every word from Latin -ārius →Every word from Latin iānuārius →