Apparently you need one or more suitable dictionaries for language learning. If you use iOS device, a dictionary app will be a good companion such as the following MDict.
MDict is a very practical dictionary app developed by Octopus Studio, and designed for both iPhone and iPad. The iOS app doesn’t have any preset dictionary, strictly speaking, MDict is an open dictionary platform, using a built-in web browser the dictionary app allows you download pre-built dictionary data by others from the Internet or import dictionary data from your computer, and the dictionary app supports pronunciation including English, French, Portuguese, Chinese, and Japanese. Moreover, it also supports rich text formatted content, while Favorites and Search history allow you to review those useful words.
MDict with a size of 2.8 MB is compatible with iPhone (optimized for iPhone 5), iPod touch and iPad running iOS 4.3 or later. The iOS app is free for a limited time at present. If you’re interested, jump to App Store for more details.