And Yes , you can have have a common name for both a MView and its base table.As Jeneesh already demonstrated, creating a MView with same name as of an existing table is not possible.
If you check DBA_OBJECTS properly, there are 2 separate columns - OBJECT_NAME and OBJECT_TYPE
The latter col distinguishes between them, even though the former col is same.
Hope this is clear.
select owner,object_name,object_type from dba_objects where Upper(object_name) like 'X';