What does adagio mean?
The definition of adagio
A*da”gio, a. & adv.
Etym: [It. adagio; ad (L. ad) at + agio convenience, leisure, ease. See Agio.] (Mus.)

Slow; slowly, leisurely, and gracefully. When repeated, adagio, adagio, it directs the movement to be very slow.

A*da”gio, n.
A piece of music in adagio time; a slow movement; as, an adagio of Haydn.