Where does “toponymous” come from?

toponymous (English) comes from English ous, from English ou, from Afrikaans ou, from Dutch oud, from Middle Dutch out, from Old Dutch ald, from Proto-West Germanic ald, from Proto-Germanic aldaz — to grow, nourish.

Ancestry of “toponymous”, step by step

toponymous traces back through two separate lines of ancestry.

via English ous

StepLanguageWordMeaning
1Englishousplural of ou
2EnglishouA probably extinct species of Hawaiian...
3AfrikaansouAn old fellow, guy, bloke; attributive form of...
4Dutchoudold
5Middle Dutchoutold
6Old Dutchald
7Proto-West Germanicaldold
8Proto-Germanicaldazold, grown up
9Proto-Indo-Europeanh₂eltós
10Proto-Indo-Europeanh₂él-to grow, nourish

via English toponym

StepLanguageWordMeaning
1EnglishtoponymA placename; A word derived from the name of a...
2EnglishtoponymyLexicological study of place names; a branch of...
3English-onymyUsed to form nouns describing the study,...
4Latin-iaUsed to form a feminine abstract noun, usually...
5Latin-iusforming adjectives from nouns; nominative neuter...
6Proto-Italic-jōsForms comparative adjectives
7Proto-Indo-European-yósCreates adjectives from noun or verb stems
Every word from Proto-Indo-European h₂él-