Frame
FRAME element defines a sub window in a window as a frame. A FRAME element is defined within the context of a FRAMESET that defines the rows and columns of a related group of frames. Web browsers treat frame as a separate window within a window. Each frame window can load its own page content, independent of other frames or windows. For Example:
<FRAMESET COLS="145,*">
<FRAME NAME="mainnav" SRC="mainnav.html">
<FRAME NAME="maincontent" SRC="index.html">
</FRAMESET>