Monea Castle has round corner towers, but they are not the free-standing round towers such as the Devenish Round Tower or the many others found on monastic sites all around Ireland.
Fascinated to find this thread as I have just returned from a visit to my mother's home place just across the hill from Boho. Still remember the smiles from my uncle and aunt as they corrected my pronunciation the first time I read off Boho from a road-sign. It's not the only local name which gets shortened. Aughakillymaude (home of the Mummers' Centre) would appear to have five syllables but somehow gets condensed to three (Och-kli-mod).