Merriam-Webster uses a very permissive standard for grammar compared to most other usage guides. I like them, but you have to be careful following their advice

Merriam-Webster uses a very permissive standard for grammar compared to most other usage guides. I like them, but you have to be careful following their advice. If you read their words fairly, you will note they say that "comprised of" is rejected by some readers. It's the whole descriptive vs. prescriptive thing, and MW explicitly adopts a descriptive standard (they say so in their preface). A good introduction to this larger question is David Foster Wallace's (excellent) essay in review of Bryan Garner's (fantastic) usage guide (http://harpers.org/wp-content/uploads/HarpersMagazine-2001-04-0070913.pdf http://harpers.org/wp-content/uploads/HarpersMagazine-2001-0...). If you are interested in usage, and are not familiar with Garner's book, I recommend it. (http://www.amazon.com/Garners-Modern-American-Usage-Garner/dp/0195382757 http://www.amazon.com/Garners-Modern-American-Usage-Garner/d...) It is superior to MW for most writers' purposes. (For students of linguistics, MW might win out.) Garner, incidentally, doesn't much like "comprised of" -- http://www.lawprose.org/blog/?p=2385 http://www.lawprose.org/blog/?p=2385 (“invariably inferior”).