The good vision is from Allah, and the dream is from the devil. So, if any of you has a dream of which he is afraid, let him spit on his left and seek refuge with Allah from its evil, for it will not harm him

The "vision" and the "dream" both refer to what the sleeper sees during his sleep. However, "vision" usually refers to what one sees of what is good and pleasant, whereas "dream" mostly refers to what one sees of what is evil and ugly, and both can be used interchangeably.
Types of visions: 1- Good vision: This is a true dream and glad tidings from Allah that one sees or that is seen for him. 2- Self-talk: This is something about which one talks to himself when awake. 3- Divilish vision: The devil's attempts to sadden, frighten, and horrify the son of Adam and cause him to experience grief.
Based on what is mentioned about the types of good vision, one should do three things: praise Allah for it, take it as a good omen, and talk about it to those whom he likes, not to those whom he dislikes.
For disliked vision, one should do five things: seek refuge with Allah from its evil and from the devil's evil; spit three times on his left upon getting up; never mention it to anyone; and in case he wants to go back to sleep, he should sleep on his other side, and it will not harm him.