Something that's lyrical is beautifully full of emotion. Don't be surprised if a lyrical passage in the book you're reading makes you cry a little bit.
The word lyric, and its connection to the words of a song, provides one hint about the adjective lyrical, which can mean "appropriate for singing." When a movie, book, dance, or work of art gives you the same feeling as the most beautiful music, you can also describe those things as lyrical. The musical connection goes all the way back to the Greek root word, lyra, or lyre.