Juice is a liquid that comes from plants, animals or fruit. The juice from fruit is often made into a drink. Some juices that are often made into drinks are apple, orange, tomato, pineapple, grapefruit, guava, mango, passionfruit, carrot, watermelon, cranberry, grape, lemon and lime, but there are many others.
In the United Kingdom the name of a fruit or fruits followed by juice can only legally be used to describe something which is 100% fruit juice. This is because of the Fruit Juices and Fruit Nectars (England) Regulations and the Fruit Juices & Fruit Nectars (Scotland) Regulations 2003.
If something has a lot of juice in it, it is said to be juicy. Juice does not have to be a drink. It can just be a liquid contained in something.