Where does “ratably” come from?

ratably (English) comes from English ratable, from English rate, from French rate, from French rat, from Middle French rat, from Old French rat, from Old High German rato, from Proto-Germanic ratō — to scrape.

Ancestry of “ratably”, step by step

ratably traces back through two separate lines of ancestry.

via English ratable

StepLanguageWordMeaning
1EnglishratableAble to be evaluated with a rating
2EnglishrateThe worth of something; value; The proportional...
3Frenchratespleen; female equivalent of rat; female rat;...
4Frenchratrat; sweetheart; scrooch
5Middle Frenchratrat
6Old Frenchratrat rodent
7Old High Germanratorat
8Proto-Germanicratō
9Proto-Germanicrattazrat
10Proto-Indo-EuropeanHreh₃d-to scrape

via English ly

StepLanguageWordMeaning
1EnglishlyAbbreviation of light-year
2VietnameselyAlternative spelling of li
Every word from Proto-Indo-European Hreh₃d-
ratably — Etymology, Origin & Word History | Etymology Explorer