Ace
The short version
A point won outright on the serve, when the receiver cannot return it legally.
From the rulebook
Points are scored by the serving side when it serves an ace (a serve which is untouched by the receiver’s hand) or wins a rally (except as provided by Rule 3.4.D.4.b, Late start.) When the serving side loses one rally in singles or two rallies in doubles, it loses the serve (except as provided by Rule 4.2.A, Server.) Losing the serve is called an “out.”
— One-wall · Rule 1.4 Points and outs
Related
Where it shows up
- One-wall · Rule 1.4 Points and outs Points are scored by the serving side when it serves an ace (a serve which is untouched by the receiver’s hand) or wins a rally (except as …
- Four-wall · Rule 1.4 Points and outs Points are scored by the serving side when it serves an ace (a serve which is untouched by the receiver’s hand) or wins a rally (except as …
In GAA / 60×30 rules
- GAA rules call any point won directly from the serve an ace, when the receiver cannot return the serve legally (GAA rule 1.4).