1510s, from Latin conformationem (nominative conformatio) "a symmetrical forming," noun of action from past participle stem of conformare (see conform).
conformation con·for·ma·tion (kŏn'fər-mā'shən)
n.
One of the spatial arrangements of atoms in a molecule that can come about through free rotation of the atoms about a single chemical bond.
any one of the infinite number of possible spatial arrangements of atoms in a molecule that result from rotation of its constituent groups of atoms about single bonds.