freely jointed chain

in polymers
A hypothetical @[email protected] molecule consisting of infinitely thin rectilinear segments uniform in length; each segment can take all orientations in space with equal @[email protected], independently of its neighbours. For models in which the segments are not all uniform in length, the name 'random-walk chain' has been used.
Purple Book, 1st ed., p. 50 [Terms] [Book]