English language students are often uncertain when it comes to the use of the prepositions between and among, and it is easy to see why. They are used in similar situations, are occasionally interchangeable, and are frequently followed by a plural noun. They are also often poorly defined and differentiated in grammar sources, which leads to further confusion.
Let's start at the beginning. The most basic rule to remember for these two prepositions is:
Between should be used when referring to someone or something positioned in the space separating two distinct things.
Among should be used when referring to someone or something in a position where they are surrounded or in the middle of a crowd, group, or mass of objects.
For example, take a look at this picture:
There are two trees, clearly separated, and the deer is positioned in the space separating them. Therefore the deer is between the trees.
In the picture above, the deer is surrounded by a group of trees, therefore the deer is among the trees.
Let's look at "between" and "among" on their own.