Why do you think the book Anthem is called Anthem?

Answer 1

It's an interesting choice of title. The author had only recently departed the Soviet Union, so it's possible that command of English might have had some impact. I'm sure there are serious students of Rand that know precisely what she meant, but here's my take on it:

Anthem is a song that a group rallies around in expression of their loyalty to something.

The book was about discovery of the individuality of oneself, as expressed by re-discovering the word "I".

"I" became the anthem for those that rejected the collectivist ideals.