It is a must have app for music lovers:

Listen to the songs in your music library with synced lyrics.
Discover the FloatingLyrics™ feature to enjoy synced lyrics while playing your favorite songs with Spotify, Play Music and any other music app.
Search lyrics for any song you love:
Instantly get the lyrics you’re looking for and play the song from Youtube or Spotify
Can’t remember the song title? Simply type part of the lyrics to find the song.
Identify lyrics for music playing around you:
With a simple tap you can magically identify the song and the lyrics from the Radio, TV or any other audio source.
Your favorite and identified lyrics will be stored in your personal profile, and can also be found on musixmatch.com under ‘identified songs’.

musixmatch is also the app providing lyrics to a z lyrics
Additional key features

Cast music and lyrics to your TV with Chromecast
Advanced features like Sleep timer, Equalizer
Automatically fetch song info and coverart for your songs
Android Wear and Android TV support
LOVE MUSIXMATCH?
Like us on Facebook: http://www.facebook.com/musixmatch
Follow us on Twitter: http://twitter.com/musixmatch

Problems? Feedback?
The more you tell us, the better Musixmatch will be.
https://support.musixmatch.com