Fault
Let
I am not sure but just call your local tennis place
Do you mean "let"? If so, a let is when a serve touches/nicks the net AND lands in on a player's serve. People call "let" so the server knows their serve hit the net. If a server hits a let, they get to redo their serve.
Sports where you serve a ball include tennis, volleyball, badminton, table tennis, and pickleball. In tennis, the serve starts each point, while in volleyball, the serve initiates play and is crucial for scoring. Badminton and table tennis also require a serve to start each rally, and in pickleball, the serve is used to begin each point as well.
Losing your serve is when you lose the game in which you were serving, it is said the oppenent (whoever that may be) broke someones (whoever was servings) serve. If you win the game then you held your serve.
For a given play, there is only one service unless there is a "let" (ball touches the net or opponent not ready). A failed service is a point for the opponent. This is different from tennis where a service fault allows another serve.
In a game of tennis, you serve from behind the baseline on the right side of the court.
Badly.
a serve
You can hit an underhand serve in tennis; however, the overhand serve is more effective because it is more powerful. That is why you don't see the underhand serve used much.
In tennis, you serve the ball from behind the baseline into the diagonally opposite service box on the other side of the net.
A tennis ball!