Wordd - Quickly look up vocabulary, abbreviations, acronyms, slang
Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.
Eunoia - Words that don't translate
Yak Tack - remember. words.
Word of The Hour - Easily expand your vocabulary with a new word, every hour 🕖
Words For That - the reverse-Urban Dictionary of the internet