The struggle a character is to get what the character wants is known as this.
What is conflict?
A speech given by a single character, usually fairly long.
What is a soliloquy?
The smallest structural division traditionally found in a play.
What is a scene?
This is the part of the stage you should move to, if instructed to move "Downstage right."

What is G?
Named based on theater's origins, this group observes the action and often comments on it.
What is a Greek chorus?
The group of actors who performs the play.
What is the cast?
A comment made by one character intended not to be heard by one or more other characters on stage.
What is an aside?
There are several reasons a scene might change. These are two of those reasons.
It is usually a change: Time (later in the day, the next day, etc), place, mood, same place and time but new characters or perspective, etc.
The area to the side of the stage, where actors often wait before entering.
What are the wings?
The term for an outdoor theater space, usually without a roof or walls.
What is an amphitheater?
When we read novels, we call it a book. When we read plays, we call it this six-letter word.
What is the script?
The general name for small items characters manipulate and use on stage.
What are props?
The large divisions of a play. Shakespeare's works always had five.
What are acts?
The (often sunken) area just in front the stage where musicians sometimes play.
What is the orchestra pit?
Spell the job of the person who originates the story of the play.
What is a playwright?
The instructions and suggestions included in the play, never spoken, but only read by the cast and crew.
What are the stage directions?
The term for one actor -- whether intentionally or unintentionally -- taking focus from another actor at the wrong time.
What is "upstaging"?
The acting term for a moment of silence taken between delivering lines, often used to heighten tension.
What is a beat?
This is the arch that frames the front of the stage:

What is the proscenium?
The act of making up lines or gestures in the moment of performance.
What is to ad-lib?
Literally translated as "God in the machine," this phrase now refers to the practice of overly contrived solutions to complex conflict.
What is "Deus ex machina"?
The general term for a reminder that it's a particular actor's turn to speak.
What is a cue?
Old term for the exit of many characters at once.
What is exeunt?
The invisible and most often impermeable barrier that separates the actors from the audience.
What is the fourth wall?
A type of theatrical stage design that has audience members sitting fully encircling the stage.
What is theater in the round?