A script can be difficult enough to read if you aren't familiar with it, but the vocabulary and abbreviations can be a bit elusive. Here are some descriptions of some common script terms:

TERM DEFINITION
Ellipsis Ellipses, or dot-dot-dots (…), are used to communicate a trailing thought in dialogue. As opposed to dashes, ellipses imply that there should be a pause before the next action or spoken line of dialogue.
EXT EXT. stands for exterior; or when any shot takes place outside.
INT INT. stands for the interior; or when any shot takes place inside.
VO VO refers to voiceover; or when any character narrates over actions. Most of the time, VO comments on thematic beats rather than what’s happening at any given moment.
CUT TO Changing suddenly from one shot to another.
FADE IN/OUT A FADE is a transition that is almost exclusively used to mark the beginning and end of a script. Sometimes screenwriters use FADE TO BLACK or FADE FROM BLACK instead of simply FADE IN or FADE OUT.
POV When we see POV in a script, it usually means that the camera is meant to substitute for the first-person point of view of a character.
Superimpose Implies that the object should be “superimposed” onto a shot to communicate something (usually setting).
MS Medium camera shot.
CU Close-up camera shot.
WS Wide camera shot.
ECU or XCU Extremely close-up camera shot.
OTS Over-the-shoulder camera shot.
BG A term used for the word “background.”
SFX Practical (usually) special effects.
VFX Digital special effects.