Where does “мать-одиночка” come from?

мать-одиночка (Russian) comes from Russian одиночка, from Russian одино́кий, from Russian оди́н, from Old East Slavic оди́нъ, from Proto-Slavic edìnъ, from Proto-Balto-Slavic edīˀnas, from Proto-Balto-Slavic aiˀnas, from Proto-Indo-European óynos — one; single.

мать-одиночка (Russian): single mother a woman raising a child on her own

Definitions

single mother a woman raising a child on her own

Ancestry of “мать-одиночка”, step by step

мать-одиночка traces back through two separate lines of ancestry.

via Russian одиночка

Step	Language	Word	Meaning
1	Russian	одиночка	loner, singleton one who lacks or avoids company
2	Russian	одино́кий	solitary, single, lone
3	Russian	оди́н	—
4	Old East Slavic	оди́нъ	—
5	Proto-Slavic	edìnъ	one
6	Proto-Balto-Slavic	edīˀnas	—
7	Proto-Balto-Slavic	aiˀnas	one
8	Proto-Indo-European	óynos	one; single

via Russian мать

Step	Language	Word	Meaning
1	Russian	мать	mother
2	Old East Slavic	мати	mother
3	Proto-Slavic	mati	mother
4	Proto-Balto-Slavic	mā́ˀtē	mother
5	Proto-Indo-European	méh₂tēr	mother

Every word from Proto-Indo-European óynos →Every word from Proto-Balto-Slavic aiˀnas →Every word from Proto-Balto-Slavic edīˀnas →