What's the difference between a router and a wireless access point?

I’m in student accommodation and currently connect my imac to the internet via an ethernet port in the wall. I’ve just purchased a new Macbook and would like to connect to the internet wirelessly.

I’ve been told that I am not allowed to connect a router to do this, but should purchase a wireless access point.

What’s the difference?

I’m thinking of buying the apple time capsule as i need an external hard drive and the wireless printing etc makes it ideal.

Apple support tell me that it has routing features, am I able to ‘turn these off’?

Hope you can help!