As nouns the difference between cees and cess
is that
cees is , the name of the letter c while
cess is (british|ireland) an assessed tax or
cess can be (rail transport) the area along either side of a railroad track which is kept at a lower level than the sleeper bottom, in order to provide drainage.
As a verb cess is
(british|ireland) to levy a or
cess can be (obsolete) to cease; to neglect.