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.
A short, sharp or high note or noise, as of a bird or insect.
A pulse of signal whose frequency sweeps through a band of frequencies for the duration of the pulse.
To make a short, sharp, cheerful note, as of small birds or crickets.
To speak in a high-pitched staccato.
To modify (a pulse of signal) so that it sweeps through a band of frequencies throughout its duration.
To speak rapid insulting comical banter back and forth.