Why is associated with the in poem A Thing of Beauty by John Keats?

You're asking about what is associated with the "in" in John Keats' "A Thing of Beauty." It seems like you might be referring to a specific line or phrase. To help me understand your question, could you please provide the full line or the lines surrounding "in"?

For example, is it:

* "A thing of beauty is a joy for ever:"

* "Its instant wakes me, like a sweet perfume"

* "When on my inward eye the bright and fierce"

Once you provide the context, I can tell you what Keats is associating with the "in" in that specific instance.