The Roman Map of Britain Maiona River Meon, Hampshire

Maina var. Mauia (R&C 238) next

    Maina is probably an error for Maiôa (for Maiona). 

    See also the adjectival(?) use in the name of the Island of Harris Maiona Eirimon.

    The river Meon is recorded as Meonea a 790, and the village Meone 880-5. Wickham (su5711) is recorded in the Ravenna Cosmography as Morionio (R&C 30) for Maionio. The name is the same as the continental Moenus Main.

    I must suggest that Ptolemy's Magnus portus arose from the name of the Meon. It joins the Solent at the mouth of the Southampton Water, where Magnus portus is traditionally placed.
MegaV limhn (Ptolemy II 3 3), Upo de ton Megan limena nhsoV Ouhktis (Ptolemy II 3 14)