Router vs Switch

Need some help...don't know if I need a router or switch (and what is the difference)?

I have a DSL modem hooked to a phone line. It has only one ethernet wired output (I use for computer). I would like to plug-in my BluRay player.

Do I need a switch or a router? I do not want wireless, just mutiple wired inputs to the internet. Thanks.

Thanks Mike...All this gets more and more complicated.