The apparent displacement of an object as it is viewed from two different positions is known as

That's called 'parallax'.

To see it happen, go outside, hold your arm straight out in front

of your face and stick your thumb up. Close one eye, and notice

where your thumb appears against the houses across the street.

Now, don't move your arm, but just close the first eye and open

the other one. You'll see your thumb jump in front of a different

house. The angle that your thumb appeared to move is its parallax.