Place nouns are words such as hospital, university, prison, library, etc. You can use them with or without articles. Both are correct but have different meanings.
- She is in hospital at the moment.
(no article/we think of a hospital as a place for sick people)
- Let’s meet outside the hospital.
(article/we think of a hospital as a building)
- Books are kept in libraries.
(no article/we think of a library as a place to keep books)
- There is a library next to the shopping centre.
(article/we think of a library as a building)