The Collaborative International Dictionary of English v.0.48:

Acceptor \Ac*cept"or\ (#; 277), n. [L.]
   One who accepts; specifically (Law & Com.), one who accepts
   an order or a bill of exchange; a drawee after he has
   accepted.
   [1913 Webster]

WordNet (r) 3.0 (2006):

acceptor
    n 1: (chemistry) in the formation of a coordinate bond it is the
         compound to which electrons are donated
    2: the person (or institution) who accepts a check or draft and
       becomes responsible for paying the party named in the draft
       when it matures

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

Finite State Machine
acceptor
Finite Automata
Finite Automaton
Finite State Automata
Finite State Automaton
NFA

    (FSM or "Finite State
   Automaton", "transducer") An abstract machine consisting of
   a set of states (including the initial state), a set of
   input events, a set of output events, and a state transition
   function.  The function takes the current state and an input
   event and returns the new set of output events and the next
   state.  Some states may be designated as "terminal states".
   The state machine can also be viewed as a function which maps
   an ordered sequence of input events into a corresponding
   sequence of (sets of) output events.

   A deterministic FSM (DFA) is one where the next state is
   uniquely determinied by a single input event.  The next state
   of a nondeterministic FSM (NFA) depends not only on the
   current input event, but also on an arbitrary number of
   subsequent input events.  Until these subsequent events occur
   it is not possible to determine which state the machine is in.

   It is possible to automatically translate any nondeterministic
   FSM into a deterministic one which will produce the same
   output given the same input.  Each state in the DFA represents
   the set of states the NFA might be in at a given time.

   In a probabilistic FSM [proper name?], there is a
   predetermined probability of each next state given the
   current state and input (compare Markov chain).

   The terms "acceptor" and "transducer" are used particularly in
   language theory where automata are often considered as
   abstract machines capable of recognising a language (certain
   sequences of input events).  An acceptor has a single
   Boolean output and accepts or rejects the input sequence by
   outputting true or false respectively, whereas a transducer
   translates the input into a sequence of output events.

   FSMs are used in computability theory and in some practical
   applications such as regular expressions and digital logic
   design.

   See also state transition diagram, Turing Machine.

   [J.H. Conway, "regular algebra and finite machines", 1971, Eds
   Chapman & Hall].

   [S.C. Kleene, "Representation of events in nerve nets and
   finite automata", 1956, Automata Studies. Princeton].

   [Hopcroft & Ullman, 1979, "Introduction to automata theory,
   languages and computations", Addison-Wesley].

   [M. Crochemore "tranducters and repetitions",
   Theoritical. Comp. Sc. 46, 1986].

   (2001-09-22)


Bouvier's Law Dictionary, Revised 6th Ed (1856):

ACCEPTOR, contracts. The person who agrees to pay a bill of exchange drawn
upon him. There cannot be two separate acceptors of a bill of exchange, e.
g. an acceptance by the drawee, and another for the honor of some party to
the bill. Jackson v. Hudson, 2 Campb. N. P. C. 447.
     2. The acceptor of a bill is the principal debtor, and the drawer the
surety.  He is bound, though he accepted without consideration, and for the
sole accommodation of the drawer.  By his acceptance he admits the drawer's
handwriting, for, before acceptance it was incumbent upon him to inquire
into the genuineness of the drawer's handwriting. 3 Burr. 1354; 1 Bla. Rep.
390, S. C.; 4 Dall. 234; 1 Binn. 27, S. C. When once made, the obligation of
the acceptor is irrevocable. As to what amounts to an acceptance, see ante,
Acceptance; Chitty on Bills, 242, et. seq.; 3 Kent, Com. 55, 6; Pothier,
Traite du Contrat de Change, premiere part. n. 44.
     3. The liability of the acceptor cannot in general be released or
discharged, otherwise than by payment, or by express release or waiver, or
by the act of limitations. Dougl. R. 247. What amounts to a waiver and
discharge of the acceptor's liability, must depend on the circumstances of
each particular case. Dougl. 236, 248; Bayl. on Bills, 90; Chitty on Bills,
249.