The Phrontistery – “The Phrontistery is dedicated to expanding the study and enjoyment of English words and wordplay through the medium of the Internet.”
Addictionary – “An online open dictionary for words that don’t exist in the English language, but perhaps should.” Today’s WotD as an example: napoplectic. adj. the state a mother lapses into when their kid won’t go down for a nap.
Omniglot – “A guide to the writing systems and languages of the world. It also contains tips on learning languages, language-related articles, quite a large collection of useful phrases in many languages, multilingual texts, a multilingual book store and an ever-growing collection of links to language-related resources.”