Thanks for all the responses. Only one thing remained unclear: what is
a finish sander. Is it a unifying term for a couple different types of
senders? (A couple of linkes to actual sanders would be useful.)

Yes, I think a finish sander is just a sander suitable for finish work.
Random orbital, 1/4 sheet jitterbug, profile, etc. Each type has uses
that it's better for than others: the ROS and jitterbug are good for
large, flat areas; the profile sanders usually have different
attachments to sand various shapes and corners.

The only sander mentioned so far that's not a finish sander is a belt
sander - I steer clear of them because an unskilled person (like
myself) can really damage the wood with one of those. It's good for
taking a lot of material off quickly, but can also leave an uneven
surface if not used carefully.

Also, is hook&loop a synonym for velcro?

yes. Velcro is actually a brand name. most of the 5" round ROS just
have a pad on the bottom that can accept adhesive backed paper OR
adhesive backed hook & loop pads. If you go the adhesive route, just
be sure to peel the paper off while it's still warm. Once the adhesive
cools down, it gets harder to pull off (not impossible, just a littler
harder).