Source : Webster's Revised Unabridged Dictionary (1913)

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.