What is the meaning of це?

horse's tooth

genitive/accusative/locative of ти (ti)

Used with reflexive verbs.

The alternative forms with an initial н- (n-) in the third person are used after a preposition.

The plural forms with an initial и- (i-) are unstressed.

The forms with an initial й- (j-) or ї- (ji-) in the third person non-feminine dative/accusative cases are used at the beginning of the sentence and when they are stressed.

The instrumental and locative cases are never used without a preposition.

alternative spelling of цэ ()

this, it

that

nominative/accusative neuter singular of цей (cej)

Source: wiktionary.org