pegacorn UK /ˈpɛɡ.əˌkɔːn/US /ˈpɛɡ.əˌkɔɹn/ noun1 •(informal) A horned Pegasus or a winged unicorn.It was a flying horse — no, a unicorn — or a pegacorn? — feathery wings outstretched. — 2006 formspegacorns