A vocal performance with no instrumental accompaniment.
Singing solely or mainly without instrumental accompaniment.
Related to a form of purely vocal music mostly associated with American college performance groups.
In a manner of a choir with no instrumental accompaniment; literally, "in the style of the (Sistine) Chapel (in Rome)", such as a musical Mass done a cappella.
An instrumental composition in several movements.
A love song that is sung directly to one's love interest, especially one performed below the window of a loved one in the evening.
To sing or play a serenade for (someone).