For a convenient, interesting, user-friendly online dictionary, try The Longman Dictionary of Contemporary English. You can type in a word and get clear, easy-to-understand definitions, variations on the word, and topic labels. You can click on topic labels to access the “Topic Dictionary.” Here, you will see a colorful list of words associated with a general topic. For example, under “government” you will find, among many others, “administration, agency, capital, chief, city hall, city-state, internal, kingdom, public, staff, state.” It’s a great way to show the meaning of the words, how they are used, and the various related words and concepts. Try it today!