Stobaeus on Stoic Ethics 13

The Stoics call "practices" the love of music, of letters, of horses, of hunting, and, broadly speaking, the so-called general crafts. 

They are not knowledge, but they leave them in the class of virtuous conditions, and consistently they say that only the wise man is a music lover and a lover of letters, and analogously in the other cases. 

They give a definition of a "practice" as follows: a method using a craft or some part of a craft that leads us to what is in accord with virtue. 

IMAGE: Rembrandt, The Scholar at the Lectern (1641)