Spanish: topographic name for someone who lived on or by a hill
or ridge, Spanish cerro, from Latin cirrus ‘bristle’,
‘hair’, ‘hackles’, or possibly a nickname for someone with a ridge of
spiky hair like an animal’s hackles. Alternatively, it may be a
habitational name from a place named with this word (in the sense
‘ridge’), as for example El Cerro in Salamanca province.
Italian: topographic name from cerro ‘turkey oak’, ‘cerris’
(Quercus cerris).
Dictionary of American Family Names, Oxford University Press, ISBN 0-19-508137-4