Where does “cinquanta” come from?

cinquanta (Old Occitan) comes from Vulgar Latin cinquaginta, from Latin quinquaginta, from Proto-Indo-European penkʷēḱomt, from Proto-Indo-European *pénkʷedḱomt.

Ancestry of “cinquanta”, step by step

StepLanguageWordMeaning
1Vulgar Latincinquagintafifty
2Latinquinquagintafifty; 50
3Proto-Indo-Europeanpenkʷēḱomt—
4Proto-Indo-European*pénkʷedḱomt—
Every word from Proto-Indo-European *pénkʷedḱomt →Every word from Proto-Indo-European penkʷēḱomt →Every word from Latin quinquaginta →