WordWeb Online

1. An expression of approval and commendation
   "he always appreciated congratulations for his work";
   - praise, kudos, extolment, pat on the back, hats off [informal], congrats [informal]

1. The act of acknowledging that someone has an occasion for celebration
   - felicitation
    
2. (usually plural) an expression of pleasure at the success or good fortune of another
   "I sent them my sincere congratulations on their marriage";
   - felicitation

Type of: approval, commendation, expression, speech act, verbal expression, verbalism

Encyclopedia: Congratulations, It's a Boy