Definition of bifold:
(n) :
(carpentry) A door, window, shutter, or divider consisting of two equal panels hinged together so that it opens by folding the panels against each other.
(n) :
A wallet, billfold, or carrying case with a single fold, so that it opens like a book.
(n) :
A sheet of paper or cardboard folded in half along a crease down the center.
(adj) :
Twofold, double.
(adj) :
Of two kinds.
(n) :
A crease or turn that causes something to double back on itself.