the sill of a door; a horizontal piece of wood or stone that forms the bottom of a doorway and offers support when passing through a doorway | the enclosing frame around a door or window opening |
the entrance (the space in a wall) through which you enter or leave a room or building; the space that a door can close | the housing or outer covering of something |
the smallest detectable sensation | the outermost covering of a pneumatic tire |
a region marking a boundary | |
the starting point for a new state or experience | |