A full shows the whole subject in the shot. From "House of Flying Daggers" (2004).
Medium Full Shot (MFS)
Generally tends to show character from knees up. "Who Framed Roger Rabbit?" (1988)
Medium Shot (MS)
Portrays the character from the waist up."Room on the Broom" (2012)
Medium Close Up (MCU)
Describes subject(s) from mid-chest up. Also know as the 2 T shot."Ghostbusters" (1984)
Close Up (CU)
Generally just off the shoulder up. "Dumbo" (1941)
Extreme Close Up (ECU)
Camera is usually framed on specific details of the face to heighten intensity whether to make something more scary as in "Coraline" (2009). Or to signify a waking moment, from reality to dream or vise-versa. As from "Lost" (2004).
Number of subjects in a shot is a simple of subtractive addition, or additive subtraction or...er...it comes down to this:
A shot with one subject (typically a character) in the frame is called a Single. Like the Framing Heights mentioned above, the camera can be positioned on the subject in any way; LA, HA, ERL, Frontal. Profile, 3/4 etc. What the below images cover are the number of subjects in shot at one time.
Here are two singles, one from "Ninja Scroll" (1993) and the other from "Master and Commander; Far Side of the World" (2003)
What do you think a shot framing two characters is called? A double? Nah, those are hits where you get two bases or a delicious hamburger. The term you are looking for is "2-Shot" as shown in These examples from "Lord of the Rings; The Two Towers" (2002), "Ghost in the Shell" (1995) and "Mark of Zorro" (1940)
Shots composed around three characters are not called triples, what are you a baseball freak or something? These are known as "3-Shots" Here are three, from "Anastasia" (1997), "Princess Bride" (1987) and "Batman; The Movie" (1966) Holy Threesomes, Batman!
If you have four folks framed in a shot you are looking at a "4-Shot" but these tend to be referred to as Crowd shots because that's a lot of folks huddled in one shot. "The Lord of the Ring; Fellowship of the Ring" (2001) and "Ghostbusters" (1984).
After a while, everything just gets called a crowd unless it's really specific in the script...Adding characters requires special attention to composition so the the shots don't get muddled. Mantis is a little hard to read below from "Kung Fu Panda" (2008). Five characters.
Six characters in a triangular pattern from "Big Hero Six" (2014).
A seven character set up interestingly composed from "Usual Suspects" (1995).
The more subjects, the more you loose track and all the characters just become texture. "Star Wars" (1977-Special Edition 1997).