Make a topic dictionary. Make a small book for each child with 6 to 8 pages. Children choose 6 to 8 related words and enter them in alphabetical order, one per page. There should be room for the word, its definition and an illustration.

While this is mainly a Literacy activity it fits in really well with other subjects. The children can focus on some key words associated with, e.g., Geography, Science, R.E. etc.