A song is a musical composition with words and music, sung together. A song may be written for a single singer, or a group of singers in harmony. It can also be written for instruments alone, and is often called an instrumental song. Songs are written and recorded for a variety of purposes, including commercial, entertainment and ceremonial occasions. There are many genres of songs, from traditional ballads to pop hits to rock and blues.
In classical music, songs are usually accompanied by piano or other instrumentation. They are intended for performance by classical artists, and they are typically written separately by a lyricist or poet and a composer. The term art song is used to distinguish these more serious compositions from folk and popular songs, which are often less structured and may include lyrics that are not directly derived from poetry or literature.
An important aspect of writing a successful song is understanding the relationship between a melody and a lyric. A songwriter must understand how to craft melodies that compliment a lyric, and how to use cadence and rhythm to convey emotion.
Research shows that music can influence people’s emotions and behavior. For example, a study of “drill” music, a type of rap with violent lyrics, found that it can induce aggressive thoughts and behaviors. But the effect is short-lived, and is lessened when the music changes to a nonviolent song.