Merriam-Webster's Collegiate Dictionary, 11th Ed.

Why it's worth it

A 1,664-page hardcover with more than 225,000 definitions and indexed spine tabs. It's the reference American style guides point to, and it's built to survive four years of getting yanked off a shelf and dropped back down again.

This is the dictionary American academic style guides actually name. Chicago, APA and MLA all treat Merriam-Webster as the standard for American English spelling and usage. When a professor tells you to check a dictionary, this is the one they mean. That matters more than it sounds — you're not just looking up a word, you're settling a question in a way your instructor will accept without argument.

The coverage runs deep enough that you'll rarely hit a wall. More than 225,000 definitions and roughly 70,000 usage examples sit across those 1,664 pages. Most entries carry two to four senses with numbered sub-senses for specialized meanings. If you're reading nineteenth-century fiction or a dense journal article, that depth is what keeps you from having to go online halfway through.

From our review of 7 dictionaries and thesauruses for students, by Genevieve Dubois, Home & Living Expert

What we like

• +This is the dictionary American academic style guides actually name
• +The coverage runs deep enough that you'll rarely hit a wall
• +The indexed spine tabs sound trivial until you use them
• +Each entry includes a date of first use, which is quietly useful for test prep

What to know

• –There's no usage panel for disputed grammar
• –It's big and it's heavy
• –Nothing digital comes with it