A Contradiction?

So I was looking up some words for a book Isaac is writing and I looked up hermitage.
This was the definition:

noun

1.
a. The habitation of a hermit or group of hermits.

b. A monastery or abbey.

2. A place where one can live in seclusion; a retreat.

3. The condition or way of life of a hermit.

What do they mean, a "group" of hermits!?!! lol It sounds like an oxymoron to me. =)