MONA, two islands of this name in the sea lying between Britain and Ireland. The one described by Cæsar, as situated in the mid-passage between both islands, and stretching out in length from south to north. Called Monarda, (Ptolemy); Monapia, or Monabia, (Pliny). Supposed to be the Isle of Man. Another Mona, (Tacitus); an island more to the south, and of greater breadth; situate on the coast of the Ordovices, from whom it is separated by a narrow strait. The ancient seat of the Druids. Now called Anglesey, the island of the Angles or English.