The Collaborative International Dictionary of English v.0.48:

Coercion \Co*er"cion\, n. [L. coercio, fr. coercere. See
   Coerce.]
   1. The act or process of coercing.
      [1913 Webster]

   2. (Law) The application to another of either physical or
      moral force. When the force is physical, and cannot be
      resisted, then the act produced by it is a nullity, so far
      as concerns the party coerced. When the force is moral,
      then the act, though voidable, is imputable to the party
      doing it, unless he be so paralyzed by terror as to act
      convulsively. At the same time coercion is not negatived
      by the fact of submission under force. "Coactus volui" (I
      consented under compulsion) is the condition of mind
      which, when there is volition forced by coercion, annuls
      the result of such coercion. --Wharton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

coercion
    n 1: the act of compelling by force of authority
    2: using force to cause something to occur; "though pressed into
       rugby under compulsion I began to enjoy the game"; "they
       didn't have to use coercion" [syn: compulsion, coercion]

Moby Thesaurus II by Grady Ward, 1.0:

20 Moby Thesaurus words for "coercion":
   argumentum baculinum, compulsion, constraint, duress,
   high pressure, intimidation, menace, menacing, pressure,
   strong-arm tactics, the big stick, the bludgeon, the club,
   the jackboot, the mailed fist, the strong arm, the sword, threat,
   threatening, violence



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

implicit type conversion
coercion

    (Or "coercion") The abilty of some compilers
   to automatically insert type conversion functions where an
   expression of one type is used in a context where another type
   is expected.

   A common example is coercion of integers to reals so that
   an expression like sin(1) is compiled as sin(integerToReal(1))
   where sin is of type Real -> Real.

   A coercion is usually performed automatically by the compiler
   whereas a cast is an explicit type conversion inserted by
   the programmer.

   See also subtype.

   (1997-07-28)


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

COERCION, criminal law, contracts. Constraint; compulsion; force.
     2. It is positive or presumed. 1. Positive or direct coercion takes
place when a man is by physical force compelled to do an act contrary to his
will; for example, when a man falls into the hands of the enemies of his
country, and they compel him, by a just fear of death, to fight against it.
     3.-2. It is presumed where a person is legally under subjection to
another, and is induced, in consequence of such subjection, to do an act
contrary to his win. A married woman, for example, is legally under the
subjection of her husband, and if in his company she commit a crime or
offence, not malum in se, (except the offence of keeping a bawdy-house, In
which case she is considered by the policy of the law as a principal, she is
presumed to act under this coercion.
     4. As will (q.v.) is necessary to the commission of a crime, or the
making of a contract, a person coerced into either, has no will on the,
subject, and is not responsible. Vide Roscoe's Cr. Ev. 7 85, and the cases
there cited; 2 Stark. Ev. 705, as to what will, amount to coercion in
criminal cases.