simple past tense and past participle of birthday

The anniversary of the day on which someone is born. / The anniversary of the day on which something is created.

(intransitive, informal) To celebrate one's birthday.

Third-person singular simple present indicative form of birthday

plural of birthday

present participle of birthday

simple past tense and past participle of happy birthday

(US) A public holiday in the USA celebrated on the third Monday of February, during which the US presidents, especially George Washington, are celebrated or remembered.

(colloquial, transitive) To wish (someone) a happy birthday.

Said or written to a person who is celebrating his or her birthday in order to convey the good wishes of the speaker or writer (literally, "may you have a happy birthday")