BIFOLD
Etymology
Adjective
bifold (not comparable)
Twofold, double.
Of two kinds.
Noun
bifold (plural bifolds)
(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.
A sheet of paper or cardboard folded in half along a crease down the center.
A wallet, billfold, or carrying case with a single fold, so that it opens like a book.
A crease or turn that causes something to double back on itself.
Source: Wiktionary
Bi"fold, a. Etym: [Pref. bi- + fold.]
Definition: Twofold; double; of two kinds, degrees, etc. Shak.
Source: Webster’s Unabridged Dictionary 1913 Edition