The head refers to the upper member of the windows master frame.
The jambs are the two vertical members of the master frame and supports the outer edge of the window (the left and right boundaries).
The frame is the entire outer portion of the window and the construct in which the sashes or other parts move.
Glazing is any process or material applied to panes of glass.
Insulated Glass Unit (IGU) are made up of individual individual units of glass, divided by a "spacer system" and can be filled with Argon or Krypton gas in double and triple pane windows.
A Sash Frame is the vinyl frame that surrounds the IGU and together they form the Sash which is the part of the window that generally moves.
The sill is the lower portion of the window, which usually protrudes out from the wall.
Muntin bars separate individual panes (also known as grilles or windowpane dividers). In most Insualted vinyl windows, the Muntin bars or grids are purely cosmetic and are between the panes for easy cleaning.