Term
Volley
Hitting the ball in the air before it bounces.
Hitting the ball before it bounces (Section 2, Definitions). A volley must be started from outside the non-volley zone (kitchen), and touching the kitchen during the volley motion is a fault (11.A, 11.A.1). Also, because of the Two-Bounce Rule, the serve and the return cannot be volleyed (10.A).
See it in a figure
This figure is from the rule "No volleying in the kitchen".
How to read the sources: numbers like (8.F.4) are rulebook sections, and links are outside sources. An "Author's note" is the author's personal experience, not an official rule.