mezzo
Italian for half or medium, used in many musical terms.
In Depth
Mezzo appears as a prefix or modifier throughout musical terminology, always meaning half, medium, or moderate. Mezzo-forte means moderately loud. Mezzo-piano means moderately soft. Mezzo-soprano describes the middle female voice. Mezza voce means half voice.
The term reflects music's deep roots in Italian — the language that has supplied most of the standard performance directions used worldwide. When a musician sees mezzo in any context, they know to aim for the middle ground — not too much, not too little. It is the musical equivalent of Goldilocks' just right.
Italian became the universal language of music largely because the first printed music instruction books were Italian, and the tradition stuck — even Japanese and Chinese orchestras use Italian tempo markings.