Where does “elfmonatig” come from?

elfmonatig (German) comes from German Elf, from English elf, from Middle English elf, from Old English ielf, from Proto-West Germanic albi, from Proto-Germanic albī, from Latin Albis, from Latin Albeus.

elfmonatig (German): eleven-month; lasting eleven months

Definitions

eleven-month; lasting eleven months

Ancestry of “elfmonatig”, step by step

elfmonatig traces back through two separate lines of ancestry.

via German Elf

Step	Language	Word	Meaning
1	German	Elf	eleven; football team, XI; elf
2	English	elf	A luminous spirit presiding over nature and...
3	Middle English	elf	elf, fairy; spirit, shade
4	Old English	ielf	elf
5	Proto-West Germanic	albi	elf, fairy
6	Proto-Germanic	albī	river
7	Latin	Albis	—
8	Latin	Albeus	—

via German Monat

Step	Language	Word	Meaning
1	German	Monat	month
2	Middle High German	mānōt	month
3	Old High German	mānōd	month
4	Proto-West Germanic	mānōþ	month
5	Proto-Germanic	mēnōþs	month
6	Proto-Indo-European	mḗh₁n̥s	moon; month
7	Proto-Indo-European	meh₁-	to measure

Every word from Latin Albeus →Every word from Proto-Germanic albī →Every word from Latin Albis →