Happybirthday是问候语吗

不是问候语，是祝福语，例如：

1、The cake had 'Happy Birthday' piped on it.蛋糕上裱了“生日快乐”的字样。

2、I wished her a happy birthday.我祝她生日快乐。

3、We all crowded into her office to sing 'Happy Birthday'.我们全都涌进她的办公室，唱“祝你生日快乐”。