Element	A component of the hierarchical structure defined by a document type definition; it is identified in a document instance by descriptive markup, usually a start-tag and end-tag. SGML
End-tag	Descriptive markup that identifies the end of an element. SGML
Engine	Software used by search services.
Entity	A special character such as & that needs to be entered with an escape sequence. An iconic entity is a small icon that is useful in lists and headings, such as a folder icon to represent a directory.
Environment Variable	Standard information that can be collected by CGI scripts. CGI scripts get their input mainly from environment variables and standard input (when using the POST method). These environment variables are set when the server executes the gateway program. The environment variable QUERY_STRING is everything that follows the question mark in the URL. This information could be added either by an isindex document, or by a form using the GET method. In the POST method, form data are read from stdin. Since the server does send an EOF at the end of the data, the environment variable CONTENT_LENGTH is included to determine how much data to read from stdin.