Adagio
Slow and calm, usually between 66 and 76 beats per minute.
What it means
Adagio comes from the Italian ad agio, "at ease", and denotes a slow, calm tempo. Common reference values lie around 66 to 76 beats per minute; these figures are historically disputed and vary considerably from edition to edition and from one era to the next. More important than the number is the attitude the word calls for: unhurried, with time for each individual note.
Within the family of tempo words, Adagio sits between Largo and Andante. Largo means an even broader, weightier slowness, while Andante is a walking tempo in which a clear forward motion remains perceptible. Adagietto is the softened form, Adagissimo the intensified one.
A movement bearing this heading is not merely slow but, as a rule, also serious, songful and expressive in conception.
In the notation
The marking stands above the first system of a movement or section, often with a qualifying word such as sostenuto, cantabile or ma non troppo. As a movement title, Adagio also becomes the name of the movement itself. Metronome figures beside it frequently come from the editor and are to be understood as guide values.
Musical use
The Adagio is the classic home of the slow middle movement in the sonata, symphony and concerto. There it carries the melodic weight of the work and forms the counterpole to the fast outer movements. It is also common as an introduction before a fast movement, for instance in slow introductions that reach the home key only after some searching. In slow movements it is further striking that the note values become small: because the pulse is slow, thirty-second notes and ornaments fill the space between the beats.
Performance practice
Count in subdivisions, or you will lose the pulse between the beats. If a quarter note is your beat, think the eighths or sixteenths along with it — this holds the motion together and keeps long notes from falling short. Plan your breathing, or your bowing, in advance, since in slow tempos both run out quickly. And keep the accompaniment in the background: in an Adagio every impurity becomes audible, because the listener has time to listen closely.