Where does “pentagonal” come from?
pentagonal (Catalan) comes from Catalan pentàgon, from Catalan penta-, from Ancient Greek πεντα-, from Ancient Greek πέντε, from Proto-Hellenic pénkʷe, from Proto-Indo-European pénkʷe — five.
pentagonal (Catalan): pentagonal
Ancestry of “pentagonal”, step by step