"Lyrics" is widely used in the poetical and musical context. This terminology refers to the words of a song or verses in a poem. A single line of the entire song/poem is called a lyric, which is the singular form of the word lyrics. To distinguish between a poem's lyrics and a song's lyrics, the latter is often referred to as "song lyrics."
Song lyrics play an integral role in making a song successful, depending on its meaning. They are the songwriter's thoughts, emotions, and experiences poured straight from their hearts, right onto the paper. When the heartfelt words of a song are coupled with the right melody, you get a masterpiece that speaks to people on a whole new level.
This is what a successful song does; it helps people feel connected and uplifts, encourages, inspires, supports, and heals the listener, depending on the song's theme.