Ensuring that a specified document always appears at the same point in a results set, or always appears on the first page of results.
Access control list (ACL)
Defines permissions to access a specific repository, a set of documents, or a section of a document.
The provision of a search user interface which prompts the user to enter additional terms to assist in ranking results, often using Boolean operators.
The Apache Foundation provides support for a wide range of open source applications, including Lucene and Solr.
A search application pre-installed on a server ready for insertion into a standard server rack.
An automated process for creating a classification system (or taxonomy) from a collection of nominally related documents.
An automated process for assigning metadata or index values to documents, usually in conjunction with an existing taxonomy.
Average response time
An average of the time taken for the search engine to respond to a query, or the average end-to-end time of a query.
Results that are selected to appear at the top of a list of results that provide a context for other documents generated and ranked by the search application.
A ranking function developed in the 1990s but still widely used. It has its origins in the tf.idf ranking function.
A widely used approach to create search queries; examples include AND, OR, and NOT—for example, information AND management.
A search query using Boolean Operators.
Changing search ranking parameters to ensure that certain documents or categories of documents appear in the results.
The placing of boundaries around objects that share similarities (e.g., taxonomy).
A process employed to generate groupings of related words by identifying patterns in a document index.
A description loosely applied by search vendors to applications using machine learning and AI techniques to determine the work context of the user and deliver personalised results.
A group of objects methodically sorted and placed into a category.
The use of computer-based statistical analysis of language to determine patterns and rules that aid semantic understanding.
The process of determining concepts from text using linguistic analysis.
A software application that enables a search application to index content in another application.
An organised list of words, phrases, or some other set employed to identify and retrieve documents.
Commercial off-the-shelf software.
A program used to index documents.
A query in one language is translated into other indexed languages (often using a multi-lingual thesaurus) so that all documents relevant to the concept of the query are returned no matter what language is used for the content.
A brief summary, generated automatically, that is then included as a description of a document in the list of results. See also Key sentence
A structured sequence of text information, but often used as a generic description of any content item in a search application.
The deconstruction of a document into a form that can be tokenised and indexed.
A site where source documents or other content objects are stored, generally a folder or folders. See also Information source
A search conducted only across documents that a user has permission to access. See also Late binding
The automatic detection of defined items in a document, such as dates, times, locations, names, and acronyms.
Two or more words considered mutually inclusive in a search, often by enclosing them in quotation marks—for example, “United Nations”.
Presentation of topic categories on the search user interface to support the refinement of a search query.
A quantity representing the percentage of irrelevant hits retrieved in a search.
A search carried out across multiple repositories and/or applications.
A search that is limited to a specific field in a document (e.g., a title or date).
A function that sets specific criteria for search results.
The time period between a document being crawled and the index being updated so that a user will be able to find the document.
A search allowing a degree of flexibility for generating hits (i.e., matches that are phonetically or typographically similar).
A set of documents used to benchmark search performance that is representative of content that will be searched on a regular basis.
A search in which the system prompts the user for information that will refine the search results.
A search result matching given criteria; sometimes used to denote the number of occurrences of a search term in a document.
List containing data and/or metadata indicating the identity and location of a given file or document.
A file that stores data in a format capable of retrieval by a search engine.
The rate at which documents can be indexed, usually specified in Gb/sec.
Inverse document frequency (IDF)
A measure of the rarity of a given term in a file or document collection.
A list of the words contained within a set of documents, and which document each word is present in, so acting as a pointer to a document.
An index whose entries identify a given word and the documents in which it appears.
A calculation utilising a recursive and self-referential algorithm.
A brief statement that effectively summarises a document, often employed to annotate search results.
A word used in a query to search for documents.
A search that compares an input word against an index and returns matching results.
The indexing process identifies the language (or languages) of the content and assigns it to appropriate language specific indexes.
Access permission checking carried out immediately before the presentation of the document to the user. See also Early binding
A process that identifies the root form of words contained within a given document based on grammatical analysis (e.g., run from running). See also Stemming
An analysis that reduces text to a set of discrete words, sentences, and paragraphs.
The study of the structure, use, and development of language.
The classification of a set of words into grammatical classes, such as nouns or verbs.
An HTML command located within the header of a website that displays additional or referential data not present on the page itself.
Data that provides information about other data (i.e., is data about data).
The analysis of the structure of language.
Natural language processing
A process that identifies content by attempting to adhere to the rules of a given language.
Natural language query
A search input entered using conventional language (e.g., a sentence).
A search that adheres to predefined attributes present within a given data source.
The process of analysing text to determine its semantic structure.
A type of matching that recognises naturally occurring patterns (word usage, frequency of use, etc.) within a document.
The procurement of linguistic concepts, generally phrases, from a given document.
The quantification of the number of relevant documents returned in a given search.
A search whose results are returned based on the proximity of given words (e.g., ‘pressure’ within four words of ‘testing’).
Query by example
A search in which a previously returned result is used to obtain similar results.
The process of analysing the semantic structure of a query prior to processing in order to improve search performance.
A value assigned to a specific result returned for a query—the first item listed has a ranking of 1, the second has a ranking of 2, and so on.
A percentage representing the relationship between correct results generated by a query and the total number of correct results within an index.
The value that a user places on a specific document or item of information. Both precision and recall are defined in terms of relevance.
The documents or data that are returned from a search.
The terms used within a search field.
An analysis based upon grammatical or syntactical constraints that attempts to decipher information contained in a document.
The use of natural language processing, computational linguistics, and text analytics to identify and extract subjective information in documents.
A search in which users receive results that are phonetically similar to their query.
An automated process that provides documents to a data extraction or parsing engine. See also Crawler
A process based on a set of heuristic rules that identifies the root form of words contained within a given document (e.g., run from running). See also Lemmatisation
Words that are deemed to have no value in an index. See also Word exclusion
Data that can be represented according to specific descriptive parameters—for example, rows and columns in a relational database, or hierarchical nodes in an XML document or fragment.
An automated process for producing a short summary of a document and presenting it in the list of results.
Automatically expanding a search by adding synonyms of the query terms derived from a thesaurus.
An analysis capable of associating a word with its respective part of speech by determining its context in a given statement.
In respect to search, the broad categorisation of objects (typically a tree structure of classifications for a given set of objects) in order to make them easier to retrieve and possibly sort.
A quantity representing how often a term appears in a document.
The term frequency.inverse document frequency formulation gives a score that is proportional to the number of times a word appears in the document offset by the frequency of the word in the collection of documents. See also BM25
A collection of words in a cross-reference system that refers to multiple taxonomies and provides a kind of meta-classification, thereby facilitating document retrieval.
The process of identifying the elements of a sentence, such as phrases, words, abbreviations, and symbols, prior to the creation of an index.
Removal of a prefix or suffix.
Information that is without document or data structure (i.e., cannot be effectively decomposed into constituent elements or chunks for atomic storage and management).
A model that enables documents to be ranked for relevance against a query by comparing an algebraic expression of a set of documents with that of the query.
A value applied to a given area of a search system (e.g., term weighting, which represents its importance with respect to other factors).
A notation, generally an asterisk or question mark, that when used in a query, represents all possible characters (e.g., a search for boo* would return book, boom, boot, etc.).
A list containing words that will not be indexed—this usually is comprised of words that are excessively common (e.g., a, an, the, etc.).