2 Answers

dic·tion·ar·y
/dikSHaneri/
Noun
A book that lists the words of a language in alphabetical order and gives their meaning, or that gives the equivalent words in a...

A reference book on any subject, the items of which are arranged in alphabetical order.
Synonyms

lexicon - vocabulary - wordbook - thesaurus - glossary

A dictionary is collection of words in one or more specific languages, often listed alphabetically (or by radical and stroke for ideographic languages), with usage information, definitions, etymologies, phonetics, pronunciations, and other information;^[1] or a book of words in one language with their equivalents in another, also known as a lexicon.^[1] According to Nielsen (2008) a dictionary may be regarded as a lexicographical product that is characterised by three significant features: (1) it has been prepared for one or more functions; (2) it contains data that have been selected for the purpose of fulfilling those functions; and (3) its lexicographic structures link and establish relationships between the data so that they can meet the needs of users and fulfill the functions of the dictionary.

A broad distinction is made between general and specialized dictionaries. Specialized dictionaries do not contain information about words that are used in language for general purposes—words used by ordinary people in everyday situations. Lexical items that describe concepts in specific fields are usually called terms instead of words, although there is no consensus whether lexicology and terminology are two different fields of study. In theory, general dictionaries are supposed to be semasiological, mapping word to definition, while specialized dictionaries are supposed to be onomasiological, first identifying concepts and then establishing the terms used to designate them. In practice, the two approaches are used for both types.^[2] There are other types of dictionaries that don't fit neatly in the above distinction, for instance bilingual (translation) dictionaries, dictionaries of synonyms(thesauri), or rhyming dictionaries. The word dictionary (unqualified) is usually understood to refer to a monolingual general-purpose dictionary