tack</dfn> is a list of <a>frames</a> that MUST be ordered
      sequentially from outermost to innermost frame.
      </p>
      <p>
      A <dfn data-lt="frame|frames">frame</dfn> is an element in the context of a <a>stack</a>
      containing information about the current execution state.
      </p>
    </section>
    <section>
      <h2>Profiling Sessions</h2>
      <p>
      A <dfn>profiling session</dfn> is an abstract producer of <a>samples</a>. Each session has:
      </p>
      <ol>
        <li>A <