źródło n (diminutive źródełko)
From Proto-Slavic *žerdlo, from Proto-Balto-Slavic *gerʔtló, from Proto-Indo-European *gʷerh₃-tlóm, from *gʷerh₃-.
Baltic cognates include Lithuanian gerklė̃ (“throat, larynx”), East Lithuanian gérklę.
Indo-European cognates include Ancient Greek ζέρεθρον (zérethron).