What is coupling?

[dvberkel]

1. A common design flaw
2. A connection between two or more components
3. A design pattern
4. A dependency in an object model

[dvberkel]

On page 5 the etymology of coupling is explained. It stems from the Latin word "copulare". It is combined from "co", meaning together, and "apere", meaning fasten.

In that sense a coupling is to connect things.

Therefore I would take answer 2: A connection between two or more components.