Caiazzo

From Italian Caiazzo, possibly from an unattested intermediate form Vulgar Latin *Caiatium, ultimately from Latin Caiatia, under possible influence from Italian -azzo (“forming pejoratives and diminutives”), of uncertain origin. UTET confused it with Calatia. It is possibly related to the name Caieta (Ancient Greek Καιήτη (Kaiḗtē)), though it is not usually related to Greek while the latter is.
The surname is from the place, and is also used as a diminutive of the personal name Caio.