Controlled Vocabulary: Domain vocabularies which have been designed in a systematic way having characteristics such as covering content, concept orientation, concept permanence among other features.

Data Mining: The application of algorithms for extracting patterns from data.

Database: A database is a software package designed to assist in maintaining and utilizing large collections of data. Databases are used when, the size of the files is large, security of the data is necessary, querying the data is important, maintaining the consistency of the data is important, and crash recovery is important.

Discourse: The overall meaning of a segment of text derived from the semantics of the words. Involves interpretation of the reader, biases, environment, etc.

Domain Knowledge: Knowledge about a specific area of study, specifically knowledge about what makes it distinct from the other areas.

Frame: A knowledge representation structure including the facts and components that describe an object or situation, along with rules to reason about the situation.

Grammar: A set of rules which define the morphology, syntax, and indirectly the semantics of a language. Application of grammar rules will discriminate between well-formed sentences and illegible ones.

Granularity: The level of fineness for a concept.

Morphology: The actual letters which make up a word. The spelling of the word. Suffixes, prefixes, conjugation and gender shifts all play a part in morphological information.

Parser: An algorithm which applies grammar rules to a sentence to identify the semantic and syntactic constituents.

Qualifiers: Words which add qualitative knowledge. They may include measures of severity, size, duration, etc.

Semantic Lexicon: A lexicon (dictionary) which includes different semantic representations of words. Distinct from syntactic lexicons which usually only include part-of-speech and spelling information.

Semantics: The symbolic meaning of a word or set of words. The definition in context.

Sublanguage: The set of grammar rules and semantics which allow all the sentences in a very specific domain. For example, the word 'windshield' would not be included in normal sentences in radiology and many poetic syntactic constructs would never be used in a discharge summary.

Syntax: The structural form of the word or set of words. On the level of a word, the syntax is the part-of-speech. Larger syntactic groups include noun groups, prepositional phrases, sentences, paragraphs, etc.

Stop Words: Very frequently occurring words in a language which add little or no information to the discourse. Examples of stop words are articles (a, the, etc) and some prepositions.