æt ðɪ ˈɛnd kʊd biː ðə lˈæst ɹᵻmˈeɪnz ʌvðə kˈɛltɪk mˈæɡəs plˈeɪn ɔːɹ mˈɑːɹkɪt, ɔːɹ ɪɾ ɪz ɐ sˈɪmpəl lˌætɪnᵻzˈeɪʃən, ænd ðɪ ˈɔːɹɪdʒˌɪn ɪz dʒˈʌst ðə kˈɛltɪk wˈɜːd ˈæstɚɹˌɪsk jˈuːənˌoʊ, ˈɔːldɚ tɹˈiː bɹˈɛtən ɡwˈɜːn, wˈɛlʃ ɡwˈɜːn, ˈaɪɹɪʃ fˈɜːn, mˈɑːdɚn fɹˈɛntʃ vˈɜːn.
at the end could be the last remains of the Celtic magus 'plain' or 'market', or it is a simple latinization, and the origin is just the Celtic word *uerno, alder tree (Breton gwern, Welsh gwern, Irish fern, modern French verne).