Between vs Among - What's the difference

The two English language prepositions Between and Among are used in similar ways, but there are differences which I will explain. Both mean "surrounded by, in the midst of, in the group of" and similar phrases.

Between is used to describe the relationship of one object with a distinct number of other objects. Between can also refer to multiple one-to-one relationships.

• My father told me to choose between a mobile phone, a laptop and a tablet.
• The differences between dolphins and porpoises are minimal.
• The discussion between the board members lasted all afternoon.
  Here, is is implied that the board members were discussing with each other in a series of small groups, or in one-to-ones.

Between is also use to describe the location of something in relation to some other things, for example:

• The river flows between two hills.
• I pushed the knife between the two pieces of wood to separate them.

Among is used when there is not a specific, countable number of objects, rather the things being described are thought of as a group:

• The lack of education among the islanders was of concern to the government.
• God walks among us.

Let's also consider a case where among and between are both correct, but will change the meaning of the sentences in which they are used:

• The rumour spread rapidly among the students.
  Here "students" is a group without a specific quantity, and since we are implying the rumour spread into this group (for example from a popular TikTok video), among is correct.
• The rumour spread rapidly between the students.
  Here, although students is still a group, the meaning has changed - the students are spreading the rumour between each other - a series of multiple one-to-one relationships, hence the use of the word between.