Camera Angle generally refers to the camera's relationship with the subject(s) in the frame.
Frontal,
Profile and
3/4 are types of angles and are covered separately. Placing the camera so it angles down on the subject is called a high angle. A set up with the camera very high over head but angled straight down is called an Aerial. Many times these shots are used to describe a setting as in the
opening sequence of "West Side Story" (1961). In the shots below, a very high angle evokes a feeling of loss or sadness. Lightning finally realizes he has found a place and others he loves but is suddenly forced away. "Cars" (2006). Below, Lola looses her boyfriend in "Run Lola Run" (1998).
Getting back to high angle or 'down-shots'; generally these are used to show inferiority, loss, low moments. We, the audience are looking down on the subject and all that implies. A perfect example is this shot from "Chocolat" (2000). The mayor, played by Alfred Molina, has fallen from his place of piety and succumbed to breaking in to a chocolate shop and destroying/eating the display. A difficult composition but well conceived to show the lowness of the character.
An ERL or Eye Ranking Level AKA Eye Ranking Angle positions the camera on a subject's horizon line. This allows the viewers to associate with or 'feel' what the character is feeling. Example below, "The Green Mile" (1999).
Low Angle, or 'up-shots' give a sense of authority to the subject. Below Mowgli's 'father figure', someone Mowgli looks up to, is shown at a gentle up-shot from "The Jungle Book" (1967).
Up-shots also describe power and the lower the camera the more powerful the character or subject becomes. As in Scar leading the hyenas to Be Prepared in the "Lion King" (1994).
Low angles also give power to settings. Maleficent's castle seems impenetrable in the camera angle below. "Sleeping Beauty" (1959).
But, as cinema has showed us, there is always a way to twist the meaning of the shot. In "Citizen Kane" (1941), Kane has just lost the election and is shown suffering the set back, his friends start to abandon him yet, the scene is shot from a low angle.
In another example, a sheriff tries to round up a posy to hunt down Butch and Sundance and the film makers went out of their way to give the man visual power; up-shot, back lighting, placing the 'hanging tree' behind him, even having him stand on a stage in front of the onlookers but the things he says and the way the onlookers respond to him strips him of any power, even to be interrupted by a bicycle salesman. "Butch Cassidy and the Sundance Kid" (1969)
When setting up your shots thing about the visual weight of the subjects in the frame, using the correct camera angle with add emphasis to your choices.