Unifilar

a. [ Uni- + L. filum a thread. ] Having only one thread; involving the use of only one thread, wire, fiber, or the like; as, unifilar suspension. [ 1913 Webster ]

Unifilar magnetometer (Physics), an instrument which consists of a magnetic bar suspended at its center of gravity by a long thread, constituting a delicate means for accurately measuring magnetic intensities, also for determining declinations of the magnetic needle. [ 1913 Webster ]