2. Terminology # T
    The following is a list of terms that are used in other
    sections of this reference.
  
- browsing context
- An environment in which UAs present documents to users.
      A tab or window in a Web browser typically contains a
      browsing context, as does an
      iframe,
      or
      frame
      elements in a
      frameset.
- case-insensitive match
- An exact comparison of two strings, codepoint for
      codepoint, except that the characters in the range
      A-Zand the corresponding characters in the rangea-zare considered to also match.
- DOM tree
- A representation of a document based on the W3C Document Object
      Model (DOM), as defined in the
      [DOM4]
      specification.
      UAs build representations of documents by parsing them and
      constructing DOM trees from them.
- flow content
- 
Flow content consists of
      flow elements
      intermixed with
      normal character data.
- HTML producers
- HTML authors (that is, people) and applications
    (such as editors and content management systems)
    that produce HTML content.
- HTML consumers
- HTML user agents; that is, applications (such as
    Web browsers) which consume HTML content.
- must
- The word must is used in this reference to mark
      document-conformance requirements that are normatively
      defined in the
      HTML5: A vocabulary and associated APIs for HTML and XHTML
      full specification.
      [HTML5].
      This reference does not itself normatively
      define any requirements. 
- newline
- Any of the following:
      
- a U+000D CARRIAGE RETURN (CR) character
- a U+000A LINE FEED (LF) character
- a U+000D CARRIAGE RETURN (CR) followed by a U+000A LINE FEED (LF) character
 
- phrasing content
- Consists of
      phrasing elements
      intermixed with
      normal character data.
- resolve a URL
- To resolve a URL to an absolute URL, as defined in
      [HTML5].
    
- space
- Any of the following:
      
- U+0020 SPACE
- U+0009 CHARACTER TABULATION (tab)
- U+000A LINE FEED (LF)
- U+000C FORM FEED (FF)
- U+000D CARRIAGE RETURN (CR)
 
- top-level browsing context
- As defined in
      [HTML5].
    
- transparent
- If the content model of a particular element
      foo is described as transparent, it means:
      
- when element foo is a child of a
        parent element bar whose content model
        is allowed to contain
        flow elements,
        then the contents of element foo may also
        contain
        flow elements
- when element foo is a child of a
        parent element baz whose content model
        restricts its child elements to only being
        phrasing elements,
        then any child elements of element foo are also
        restricted to only being
        phrasing elements
 
- UA
- An HTML user agent; that is, an application (such as a
    Web browser) which consumes HTML content.