Source : Webster's Revised Unabridged Dictionary (1913)

Pressure \Pres"sure\, n.
   Electro-motive force.

Pressure \Pres"sure\ (?; 138), n. [OF., fr. L. pressura, fr.
   premere. See 4th {Press}.]
   1. The act of pressing, or the condition of being pressed;
      compression; a squeezing; a crushing; as, a pressure of
      the hand.

   2. A contrasting force or impulse of any kind; as, the
      pressure of poverty; the pressure of taxes; the pressure
      of motives on the mind; the pressure of civilization.

            Where the pressure of danger was not felt.
                                                  --Macaulay.

   3. Affliction; distress; grievance.

            My people's pressures are grievous.   --Eikon
                                                  Basilike.

            In the midst of his great troubles and pressures.
                                                  --Atterbury.

   4. Urgency; as, the pressure of business.

   5. Impression; stamp; character impressed.

            All saws of books, all forms, all pressures past.
                                                  --Shak.

   6. (Mech.) The action of a force against some obstacle or
      opposing force; a force in the nature of a thrust,
      distributed over a surface, often estimated with reference
      to the upon a unit's area.

   {Atmospheric pressure}, {Center of pressure}, etc. See under
      {Atmospheric}, {Center}, etc.

   {Back pressure} (Steam engine), pressure which resists the
      motion of the piston, as the pressure of exhaust steam
      which does not find free outlet.

   {Fluid pressure}, pressure like that exerted by a fluid. It
      is a thrust which is normal and equally intense in all
      directions around a point. --Rankine.

   {Pressure gauge}, a gauge for indicating fluid pressure; a
      manometer.

Source : WordNet®

pressure
     n 1: the force applied to a unit area of surface; measured in
          pascals (SI unit) or in dynes (cgs unit); "the
          compressed gas exerts an increased pressure" [syn: {pressure
          level}, {force per unit area}]
     2: a force that compels; "the public brought pressure to bear
        on the government"
     3: the act of pressing; the exertion of pressure; "he gave the
        button a press"; "he used pressure to stop the bleeding";
        "at the pressing of a button" [syn: {press}, {pressing}]
     4: the state of urgently demanding notice or attention; "the
        press of business matters" [syn: {imperativeness}, {insistence},
         {insistency}, {press}]
     5: the somatic sensation of pressure; "the sensitivity of his
        skin to pressure and temperature was normal" [syn: {pressure
        sensation}]
     6: an oppressive condition of physical or mental or social or
        economic distress

pressure
     v 1: to cause to do through pressure or necessity, by physical,
          moral or intellectual means :"She forced him to take a
          job in the city"; "He squeezed her for information"
          [syn: {coerce}, {hale}, {squeeze}, {force}]
     2: exert pressure on someone through threats [syn: {blackmail},
         {blackjack}]