What is Acapella?

My favorite type of music

Acapella is a form of singing that uses nothing but the human voice to produce the sounds involved. This means that for a performance to be called acapella, it has to be entirely based on the natural human voice without incorporating instruments or backing music. The term a cappella was originally intended to differentiate between Renaissance polyphony and Baroque concertato musical styles. In the 19th century, a renewed interest in Renaissance polyphony coupled with an ignorance of the fact that vocal parts were often doubled by instrumentalists led to the term coming to mean unaccompanied vocal music.

📖Read on Wikipedia