krštenica

1. colloq. birth certificate
   Za pasoš ti treba nova krštenica. — You need a new birth certificate for the passport.
   Izvadila sam krštenicu u opštini. — I got my birth certificate at the municipal office.
2. colloq. age
   Krštenica mu više nije na strani, ali i dalje igra. — Age is no longer on his side, but he still plays.
3. (church document) baptismal certificate
   Za venčanje u crkvi tražili su nam krštenice. — For the church wedding they asked us for our baptismal certificates.

In sense 1 krštenica is the everyday name of the civil birth certificate, officially called izvod iz matične knjige rođenih. In sense 3 it is the church document certifying baptism.