Apps similar to Apple Dictionary include GoldenDict, which is open source with a free version. Other options are Wiktionary, WordReference, Dictionary.com and Wordnote Dictionary. You're spoiled for choice with Dictionaries like Apple Dictionary: we list more than 50 alternatives for the web, Android, iPhone, iPad and Mac.
Struggling to understand the acronym in your colleague's Google Docs document? tooltipr provides context directly in your browser to explain acronyms and terms you can define.
Wordo.co is the clean and social dictionary, loved by word-geeks, Wiktionary enthousiasts and students.
Cambridge Dictionary is a multi-language dictionary for students and people who are in contact with English. This online version has been offering completely free of charge since 1999 by the Univeristy of Cambridge.
United Kingdom
Multilingual dictionary. The Blueseal dictionary provides translations of words and expressions between German, English, Spanish and French in all possible combinations. It also provides a synonym dictionary for all these languages.
Access all your favorite dictionaries and other lookup services in one place.
Firefox and Chrome extension are available to easily select and lookup any text in web pages.
Client/server software, human language dictionary databases, and tools supporting the DICT protocol (RFC 2229).
xFarDic is a comprehensive multilingual dictionary developed using GTK2, wxWidgets, libxml2, under GNU/Linux and relesed under GNU/GPL.
The official Collins English Dictionary online. Comprehensive and authoritative, rely on Collins for up-to-date English with insights into language trends and usage.
Dictionary .NET is a tiny, easy and smart multilingual dictionary translating from/to 65 languages using Googles and Bing services.
Taiwan
Treegle Dictionary is a new kind of dictionary that arranges definitions in a tree format. With this format, you can see how each component of a definition contributes to the meaning of a word.
United States
The Longman Dictionary of Contemporary English Online is an online version of the CD-ROM of the Longman Dictionary of Contemporary English, Updated Edition.
