An electronic book (also e-book, ebook, electronic book, digital book) is a book-length publication in digital form, consisting of text, images, or both, and produced on, published through, and readable on computers or other electronic devices. Sometimes the equivalent of a conventional printed book, e-books can also be born digital. The Oxford Dictionary of English defines the e-book as "an electronic version of a printed book," but e-books can and do exist without any printed equivalent. E-books are usually read on dedicated hardware devices known as e-Readers or e-book devices. Personal computers and some mobile phones can also be used to read e-books.

Standards group that maintains the ONIX specification.

Formerly the Open Electronic Book Publication Standard. An open standard based on open web languages for ebooks. EPUBs can be read on most ereaders, smartphones, and tablets, including the iPhone, iPad, Android devices, Kobo, Nook, and Sony Reader. A notable exception are Kindle devices which can only read Kindle files. (See MOBI, AZW.)