[Rails] Which association is right for books table and words table?

I got two tables, books and words.

A book has many words.

However a work is not belong to a book, because a word can be used in
different book.

Which association is right for this case?

Many thanks for reply.

--
You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group.
To post to this group, send email to rubyonrails-talk@googlegroups.com.
To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.