Purple Dictionary is described as 'Dictionary from the Elementary project' and is an app in the Education & Reference category. There are more than 50 alternatives to Purple Dictionary for a variety of platforms, including Online / Web-based, Windows, Android, iPhone and Mac. The best alternative is Wikipedia, which is both free and Open Source. Other great apps like Purple Dictionary are Google Translate (Free), GoldenDict (Freemium, Open Source), Wiktionary (Free, Open Source) and Linguee (Free).
Wikipedia is a free, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Wikipedia has 17 million articles (3.5 million in English), which have been written collaboratively by volunteers around the world.
GoldenDict is an open-source dictionary program for PC computers that gives translations of words and phrases for different languages. It allows use of several popular dictionary file formats simultaneously.
At its core, Tatoeba is a large database of example sentences translated into several languages. Search example sentences translated into many languages. Add and translate your own sentences. It's collaborative, open, free, and even addictive.
dict.cc is not only an online dictionary translating from English and German to 21 languages. Its an attempt to create a platform where users from all over the world can share their knowledge in the field of translations.