Education & Reference
In this category are tools to study and learn a language, dictionaries and translation services, mathematics tools (such as calculators and equation editors), astronomy (sky maps, for example), and any other matter you are interested in. Moreover, this section also contains references where you can find answers to your questions, including encyclopedic and tutorial websites.
Most popular apps
Wikipedia
Free content, multilingual online encyclopedia written and maintained by a community of volunteers through a model of open collaboration, using a wiki-based editing system.
Anki
Anki is a program which makes remembering things easy. Because it is a lot more efficient than traditional study methods, you can either greatly decrease your time spent studying, or greatly increase the amount you learn.

sNotes – Students Notes
Students Notes is a note-taking app designed for online learners to overcome information overload, organization, and memorization challenges.
Zim
Zim brings the concept of a wiki to your desktop. Store information, link pages and edit with WYSISYG markup or directly typing some lightweight markup syntax and see it previewed as-you-type. Creating a new page is easy by either clicking on the "Create new note"...
Google Translate
Translate instantly across 100+ languages with real-time input, voice on mobile, and offline options. Free with Google integration.
DeepL Translator
Leading online translator with neural networks capturing subtle nuances, blind-tested to outperform competitors 3:1. Secure data compliance with EU laws.

Khan Academy
Khan Academy is not-for-profit with the goal of changing education for the better by providing a free world-class education to anyone anywhere.
Wolfram Alpha
Wolfram Alpha is a "Computational Knowledge Engine" - different from a search engine, it answers factual queries directly by computing the answer from structured data, rather than providing a list of documents or web pages that might contain the answer.