Probably from pegnumi (through the idea of gushing plumply); a fount (literally or figuratively), i.e. Source or supply (of water, blood, enjoyment) (not necessarily the original spring) -- fountain, well.

see GREEK pegnumi

πηγαὶ (pēgai) − 1 Occurrence

πηγὰς (pēgas) − 4 Occurrences

πηγὴ (pēgē) − 5 Occurrences

πηγῆς (pēgēs) − 1 Occurrence