Where does “tantomeno” come from?

tantomeno (Italian) comes from Italian tanto, from Latin tantus, from Latin tam, from Proto-Indo-European téh₂m, from Proto-Indo-European séh₂, from Proto-Indo-European só — this; that.

tantomeno (Italian): even less so; let alone

Definitions

even less so; let alone

Ancestry of “tantomeno”, step by step

tantomeno traces back through two separate lines of ancestry.

via Italian tanto

Step	Language	Word	Meaning
1	Italian	tanto	so much, so many; much, many; such
2	Latin	tantus	of such size, of such measure; so much, so great
3	Latin	tam	so, so much, to such an extent, to such a degree
4	Proto-Indo-European	téh₂m	—
5	Proto-Indo-European	séh₂	—
6	Proto-Indo-European	só	this; that

via Italian meno

Step	Language	Word	Meaning
1	Italian	meno	less; not; non-; minus
2	Latin	minus	nominative neuter singular of minor; accusative...
3	Proto-Italic	minos	less

Every word from Proto-Indo-European só →Every word from Proto-Indo-European séh₂ →Every word from Proto-Indo-European téh₂m →