Review for Merriam-Webster by Leobinus
Rated 4 out of 5 stars
I've used M-W for years, and haven't seen any alternative that I preferred. I subtracted a star because there are some words that you have to pay a fee to see, but those words are uncommon. The audio pronunciations are a great addition, too.
This review is for a previous version of the add-on (20080326).To create your own collections, you must have a Mozilla Add-ons account.