WordNet (r) 3.0 (2006):

flip-flop
    n 1: a decision to reverse an earlier decision [syn: reversal,
         change of mind, flip-flop, turnabout, turnaround]
    2: a backless sandal held to the foot by a thong between the big
       toe and the second toe [syn: flip-flop, thong]
    3: an electronic circuit that can assume either of two stable
       states
    4: a backward somersault
    v 1: reverse (a direction, attitude, or course of action) [syn:
         interchange, tack, switch, alternate, flip,
         flip-flop]

The Free On-line Dictionary of Computing (30 December 2018):

flip-flop
Eccles-Jordan circuit

    A digital logic circuit that can be in one of two
   states which it switches (or "toggles") between under
   control of its inputs.  It can thus be considered as a one bit
   memory.  Three types of flip-flop are common: the SR
   flip-flop, the JK flip-flop and the D-type flip-flop (or
   latch).

   Early literature refers to the "Eccles-Jordan circuit" and the
   "Eccles-Jordan binary counter", using two vacuum tubes as
   the active (amplifying) elements for each bit of information
   storage.  Later implementations using bipolar transistors
   could operate at up to 20 million state transitions per second
   as early as 1963.

   (1995-11-11)