The original Irish from which the name derives
is O'Cahill from the common personal name Cathal sometimes
anglicised Charles which may in turn derive from the Old Irish
catu-ualos meaning strong in battle.
Families of the name arose separately in different parts
of Ireland in Kerry, Galway, Tipperary and Clare. Originally
the Galway family located in the old diocese of Kilmacduagh
near the Clare border were most prominent but their position
was usurped by the O'Shaughnessys and they were declined. The
southern families flourished and the name is now most common
in countries Cork, Kerry and Tipperary while it is relatively
infrequent in its other original homes. The arms illustrated
are those of the Munster Cahills.