Where does “greatuncle” come from?

greatuncle (English) comes from English Uncle, from Middle English uncle, from Old French uncle, from Latin avunculus, from Proto-Indo-European h₂éwh₂os — maternal grandfather; maternal uncle.

Ancestry of “greatuncle”, step by step

StepLanguageWordMeaning
1EnglishUncleradiotelephony clear-code word for the letter U
2Middle Englishuncleuncle (brother of one's parents)
3Old FrenchuncleAlternative form of oncle
4Latinavunculusmaternal uncle, mother's brother; mother's...
5Proto-Indo-Europeanh₂éwh₂osmaternal grandfather; maternal uncle
Every word from Proto-Indo-European h₂éwh₂osEvery word from Latin avunculusEvery word from Old French uncle