u ‧ ni ‧ corn /ˈjuːnəkɔːn, ˈjuːnɪkɔːn $ -ɔːrn/ BrE AmE noun [countable]
[ Date: 1200-1300 ; Language: Old French ; Origin: unicorne , from Late Latin unicornis , from Latin uni- + cornu 'horn' ]
an imaginary animal like a white horse with a long straight horn growing on its head