An agglomeration is a large collection of things sitting together even though they do not really belong with each other. The pieces were not chosen to make a neat set; they just ended up in one place. You can use it for objects — a drawer that is an agglomeration of keys, tickets, and broken pens — and for bigger, more formal pictures, like a plan that is only an agglomeration of leftover ideas. It is a slightly stiff, grown-up word, and it is often not a compliment: it hints that the whole thing is messy or accidental, not well designed. Though actually, in geography the same word can sound more neutral: an urban agglomeration is simply towns that have grown into one another.