A lexical database is a lexical resource

Lexical resource

A lexical resource is a database consisting of one or several dictionaries.Depending on the type of languages that are addressed, the LR may be qualified as monolingual, bilingual or multilingual. For bilingual and multilingual LRs, the words may be connected or not connected, from a language to...

 which has an associated software environment database

Database

A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...

 which permits access to its contents. The database may be custom-designed for the lexical information or a general-purpose database into which lexical information has been entered.

Information typically stored in a lexical database database includes lexical category

Lexical category

In grammar, a part of speech is a linguistic category of words , which is generally defined by the syntactic or morphological behaviour of the lexical item in question. Common linguistic categories include noun and verb, among others...

 and synonyms of words, as well as semantic relations between different words or sets of words.