Look up what an English word means, with its part of speech, example use, synonyms and antonyms, from the openly licensed WordNet dataset.
Dictionary reads WordNet 3.1, the lexical database built at Princeton University. Toolbox holds its own copy of that data and looks a word up in it directly. The copy carries 147,982 entries.
A word rarely has one meaning. In WordNet it has senses, and the page groups them by part of speech in the order noun, verb, adjective, adverb. Each sense carries a definition, the example sentences WordNet records for it, and the other words that mean the same thing in that sense.
A synonym belongs to a sense rather than to the word, so a word with many senses answers the question many times over, with repeats. Each sense keeps its own list, and the Synonyms section under the definitions gathers all of them into one list for each part of speech. The word quiet has 13 senses which name 29 different words between them.
Antonyms are gathered the same way and are much rarer. WordNet records an opposite between two particular words, not between two meanings, so 6,645 of the 147,982 entries carry one at all. The Antonyms section says plainly when a word has none.
When no entry matches, the page offers near matches rather than nothing. The server collects words that begin with what you typed, then with the same text minus its last character, and so on for up to three characters. It ranks that pool by edit distance from your word, then by length, then alphabetically, and returns at most eight.
quiet returns four nouns, two verbs, six adjectives and one adverb.
The first noun sense is "a disposition free from stress or emotion", and its synonyms are repose, placidity, serenity, tranquillity and tranquility. The second is "the absence of sound", with the synonym silence and the example "he needed silence in order to sleep".
right has 34 senses, and ten of them record an opposite. Written out sense by sense they read wrong, left, wrong, wrong, wrong, left, center, left, wrong, wrongly — five of them the same word.
Gathered, they become four short answers. As a noun the opposite is wrong or left. As a verb, wrong. As an adjective, wrong, left or center. As an adverb, wrongly or left.
The word appears under more than one part of speech because it is a different opposite in each. A right answer is not a wrong one; a right hand is not a left one.
Nothing matches serendipitty. Trimming two characters from the end leaves serendipit, and two entries begin with it, so the page offers serendipity and serendipitous.
The same method fails on seperate, which returns nothing. No entry begins with seper, and the search only trims the end of a word, so a wrong letter in the middle puts the right word out of reach.
WordNet 3.1 was published in 2011, so a word coined after that is absent. It also holds few proper nouns and few technical terms.
No. The dataset lives on the Toolbox server, not in your browser, so every lookup needs a connection. The page says so plainly rather than show a stale answer.
No. The word reaches the server, the server answers, and nothing is written down. There is no account. The list of recent searches is held in your own browser and has a Clear button.
They are the usage examples WordNet stores. In the raw data the definition and its examples are one field, with the examples quoted at the end. Toolbox splits them apart.
Because most words have none. WordNet records an opposite between two particular words rather than between two meanings, and one was recorded for 6,645 of the 147,982 entries. Adjectives carry most of them, because an adjective usually has a clear opposite and a noun usually does not. There is no opposite of chair.
Because those words share a sense. A definition belongs to the group of words, not to one word, so every member of the group carries the same wording.
WordNet was compiled in the United States and prefers American spelling. It does record common variants side by side, so tranquility and tranquillity both appear among the synonyms of quiet.
WordNet started at Princeton University in the mid-1980s, under the psychologist George Armitage Miller. It was not written as a dictionary for readers. It was written to model how words are stored in the mind, which is why it organizes meaning rather than spelling.
The unit it is built from is the synset, short for synonym set: a group of words that can stand in for one another in some context. One synset is one concept. silence and the second noun sense of quiet belong to the same synset, which is why each is listed as a synonym of the other.
Antonymy is the exception to that structure. It joins two words rather than two synsets, because opposition is a fact about words and not about concepts. heavy and light are opposites; the synonyms of heavy are not all opposites of the synonyms of light.
Adjectives come in two kinds, a head and its satellites, where a satellite is a shade of the head meaning. Toolbox folds both into one part of speech, because the difference matters to a researcher and not to a reader.
For a word written in another script, use Script Conversion.