If I say, "shoes are to feet as gloves are to hands," I'm making an analogy. I'm saying they are analogous, in that, they are both coverings of appendages. But imagine we had a category, 'appendablorps,' which contained socks and shoes and gloves and mittens, but not shirts and shorts. Saying gloves and shoes are both appendablorps, is now category placement. But notice this is the same activity! In both cases you are saying that shoes and gloves are similar in this specific way.
Let's give another example: "Life is a dance" is an analogy.
But imagine I had a category that stood for "Dynamic And Rhythmic Interrelated System" (or "daris" for short). I could say life and dances are both darises. Again, I'm saying the same thing.
This is why words/categories/names are so important.
They let you hold on to and keep track of important analogies.