Belated birthday wishes. Is is grammatically correct? What does it mean and can it be rephrased?

Yes, "belated birthday wishes" is grammatically correct. It means that you are sending birthday greetings after the person's actual birthday has passed. The term "belated" indicates that the wishes are late. You can rephrase it in several ways, such as: - "Happy belated birthday!" - "Wishing you a happy birthday, though I'm a bit late!" - "Sorry for the late birthday wishes!" - "Though late, I hope you had a wonderful birthday!" All of these variations convey the same sentiment of wishing someone well on their birthday, even if it's after the day itself.