Where does “demonstratably” come from?

demonstratably (English) comes from English demonstratable, from English demonstrate, from Latin demonstratus, from Latin dēmōnstrō, from Latin dē-, from Latin dē, from Latin post, from Latin poste — afterwards, post; by, at.

Ancestry of “demonstratably”, step by step

demonstratably traces back through two separate lines of ancestry.

via English demonstratable

StepLanguageWordMeaning
1EnglishdemonstratableAlternative form of demonstrable
2Englishdemonstrateto show how to use; to show the steps taken to...
3Latindemonstratusshown, having been shown; proven, having been...
4Latindēmōnstrōto show, demonstrate, prove
5Latindē-of; from
6Latinof; concerning; about
7Latinpostbehind; after, since, besides, except; behind,...
8Latinposteablative singular of postis
9Proto-Italicpostibehind, after
10Proto-Indo-Europeanpóstiafter
11Proto-Indo-Europeanpósafterwards, post; by, at

via English ly

StepLanguageWordMeaning
1EnglishlyAbbreviation of light-year
2VietnameselyAlternative spelling of li
Every word from Proto-Indo-European pósEvery word from Latin dē-Every word from Proto-Indo-European pósti