Where does “Celticism” come from?

Celticism (English) comes from English Celtic, from French celtique, from Latin Celticus, from Latin Celta, from Latin Celtae, from Ancient Greek Κελτοί, from Proto-Celtic kel-to, from Proto-Indo-European ḱelh₂- — to pierce, strike; to stick; prick; stab.

Celticism (English): A Celtic custom or idiom

Definitions

  1. A Celtic custom or idiom

Ancestry of “Celticism”, step by step

Celticism traces back through two separate lines of ancestry.

via English Celtic

StepLanguageWordMeaning
1EnglishCelticOf the Celts; Of the style of the Celts
2FrenchceltiqueCeltic
3LatinCelticusCeltic; the Celtic language
4LatinCeltaa Celt
5LatinCeltaethe Celts
6Ancient GreekΚελτοίthe Celts
7Proto-Celtickel-to
8Proto-Indo-Europeanḱelh₂-to pierce, strike; to stick; prick; stab

via English ism

StepLanguageWordMeaning
1EnglishismAn ideology, system of thought, or practice that...
2English-ismUsed to form nouns of action or process or result...
3Latin-ismus-ism
4Ancient Greek-ισμόςForms abstract nouns
5Ancient Greek-μόςForms abstract nouns
6Proto-Indo-European-mósCreates action/result nouns from verb stems
Every word from Proto-Indo-European ḱelh₂-