čestitka

1. congratulations
   Primite moje iskrene čestitke na diplomi! — Please accept my sincere congratulations on your degree!
   Stigle su mu čestitke sa svih strana. — Congratulations poured in from all sides.
2. greeting card; card
   Kupila sam novogodišnje čestitke za celu porodicu. — I bought New Year cards for the whole family.
   Poslao joj je čestitku za rođendan. — He sent her a birthday card.

The reason takes na + locative (čestitka na uspehu); for holidays, za + acc. (čestitka za Božić).