Lyricism is the quality of tunefulness or melody that a piece of music has. A choir director carefully considers the lyricism of the songs she chooses for a big concert.
Something with lyricism is lyrical, or singable. This noun also captures the emotional nature of certain works of art, particularly poetry and other writing: "The poem's lyricism makes it possible for the reader to acutely experience those feelings of loss and despair." The related word lyric means "the words to a song," but originally meant "a lyric poem," from the Greek lyrikos, "singing to the lyre."