The term "vision" refers to something that a person sees. It especially refers to something unusual or supernatural that God shows people in order to give them a message.
* God sends visions to tell people something that is very important. For example, Peter was shown a vision to tell him that God wanted him to welcome Gentiles.
* The phrase "saw a vision" could be translated as "saw something unusual from God" or "God showed him something special."
* Some languages may not have separate words for "vision" and "dream." So a sentence such as "Daniel had dreams and visions in his mind" could be translated as something like "Daniel was dreaming while asleep and God caused him to see unusual things."