title: Is there a name for HTTP headers that have multiple sections separated by semicolon?
body: <p>I know that some HTTP headers that use <code>;</code> to delimit a series of values.</p>
  
  <p>Some, like <code>Prefer</code>, define a repeating set of name-value pairs:</p>
  
  <pre><code>     Prefer     = "Prefer" ":" 1#preference
       preference = token [ BWS "=" BWS word ]
                    *( OWS ";" [ OWS parameter ] )
       parameter  = token [ BWS "=" BWS word ]
  </code></pre>
  
  <p>Others, like <code>Content-Type</code>, use a variant where there is an initial section with a value followed by optional name-value pairs (still separated by a <code>;</code>):</p>
  
  <pre><code>       Accept         = "Accept" ":"
                          #( media-range [ accept-params ] )
         media-range    = ( "*/*"
                          | ( type "/" "*" )
                          | ( type "/" subtype )
                          ) *( ";" parameter )
         accept-params  = ";" "q" "=" qvalue *( accept-extension )
         accept-extension = ";" token [ "=" ( token | quoted-string ) ]
  </code></pre>
  
  <p>I am writing some code to deal with this format in header values and I want to name it right (or at least well). I guess each header just does its own thing, but it would be handy to have a common for those "sections"/"components"/"name-value pairs".</p>
  
  <p>Do various web frameworks have a common name for these?  Maybe just call them header value components and so the headers that define these can be "multi-component headers"?</p>