An electronic dictionary is an electronic reference resource that contains a library of words and their meanings, spellings, and etymologies. Sometimes electronic dictionaries serve a similar function to regular dictionaries; they are searchable and they allow one to find specific bits of information about words. In other cases, they work in the background of other programs, such as word processors, and exist only to ensure proper spelling. When a word typed into a word processor program does not match any of the words stored in the electronic dictionary, the word is marked, so the writer knows to check the word. Some electronic dictionaries can also serve as thesauruses or translation tools.
One can find an electronic dictionary on many different devices and in many places on the Internet. Some portable, battery-operated devices are made exclusively to serve as electronic dictionaries. Many phones and personal digital assistants, or PDAs, also contain integrated electronic dictionaries that can be used for checking spelling or for reference purposes. A portable electronic dictionary tends to be more convenient than a paper dictionary, as it contains many more words in a much smaller space. Also, it tends to be much faster to search an electronic dictionary than to search a paper dictionary; one only needs to type in the desired word to see it and all of the information associated with it.
There are also many electronic dictionaries on the Internet that can be accessed by anyone around the world who has Internet access. Generally, dictionaries of the same editions made by the same publishers can also be found in print form. An electronic dictionary, however, can be updated much more frequently and at any time; there is no need for a new edition of the dictionary when a few new words come into being or when the meanings of some words change in a few subtle ways. Also, companies who host online dictionaries often can make money as a result by allowing others to place advertisements on the dictionary's Web site.
Sometimes, an electronic dictionary on the Internet is run by an online community and is not officially affiliated with any formal group or publishing company. Sometimes these dictionaries are very formal and contain many links to more official dictionaries. In other cases, however, they are intended to go beyond the formal definitions of words. Some dictionaries are intended to be humorous and focus on the informal cultural uses of words.