a cappella

• a, à (Fr.) – "at", "to", "by", "for", "in", "in the style of".
• aber (Gr.) – "but".
• a cappella – in the manner of chapel music, without instrumental accompaniment.
• accelerando – gradually increasing the tempo; "accelerating".
• accentato – "with emphasis"
• acciaccatura – "crushing" – A very fast grace note that is "crushed" against the note that follows and takes up no value in the measure.

Rock singer Ian Gillan performing live with Deep Purple in 2006.

Singing is the act of producing musical sounds with the voice, which is often contrasted with speech. Air is expelled with the diaphragm as with ordinary breathing, and the pitch is altered with the vocal cords. With the lips closed, this is called humming. A piece of music created to accompany a singing part, or a cappella piece of music is called a song; someone who sings is called a singer.

Most singing involves shaping the voice to form words, but types of voice instrumental music which use open sounds or nonsense syllables ("vocables") also exist, for instance, scat singing and yodeling. Solfege assigns certain syllables to notes in the scale.