Student dictionaries tend to have fewer illustrations and special sections than children's dictionaries but more than dictionaries for adults. Some student dictionaries are designed for upper elementary and middle school students; others include high school students. I found the following three dictionaries to be especially well designed and well written.
1. "Webster's New World Student's Dictionary"
Like most student dictionaries, this book features black and white illustrations with spot color for emphasis. The pages are sturdy and the type easy to read. There are 200+ sections on word history, almost 700 synonym studies, and more than 400 biographical entries among the nearly 50,000 entries. This dictionary is written for 10 to 14 year olds. (Hungry Minds, Inc., 1996. ISBN: 0028613198)
2. "Thorndike - Barnhart Student Dictionary"
Although the book has smaller type and less artwork than similar books, it has an excellent 19 page tutorial, with "Teach Yourself" sections and puzzles. The book is designed for high school and mature junior high school students. It includes a "Basic Style Rules for Writers" section and more than 100,000 entries in its 1300 pages. (Scott Foresman - Addison Wesley, 1997. ISBN: 0673124479)3. The American Heritage Student Dictionary"
While the pages are thinner than I prefer, this dictionary for grades 6-9 is well designed. Margin notes on every page provide additional information and illustrations that enhance the standard dictionary entries. Features include sections on synonyms and the origin of words. There is also a six page "Capitalization, Punctuation, and Usage Guide." (Houghton Mifflin, 1998. ISBN: 0395902118)