Source : Webster's Revised Unabridged Dictionary (1913)

Convenience \Con*ven"ience\ (?; 106), Conveniency
\Con*ven"ien*cy\, n. [L. convenientia agreement, fitness. See
   {Convenient}.]
   1. The state or quality of being convenient; fitness or
      suitableness, as of place, time, etc.; propriety.

            Let's further think of this; Weigh what convenience
            both of time and means May fit us to our shape.
                                                  --Shak.

            With all brief and plain conveniency, Let me have
            judgment.                             --Shak.

   2. Freedom from discomfort, difficulty, or trouble;
      commodiousness; ease; accommodation.

            Thus necessity invented stools, Convenience next
            suggested elbow chairs.               --Cowper.

            We are rather intent upon the end of God's glory
            than our own conveniency.             --Jer. Taylor.

   3. That which is convenient; that which promotes comfort or
      advantage; that which is suited to one's wants; an
      accommodation.

            A pair of spectacles and several other little
            conveniences.                         --Swift.

   4. A convenient or fit time; opportunity; as, to do something
      at one's convenience.

Source : WordNet®

convenience
     n 1: the state of being suitable or opportune; "chairs arranged
          for his own convenience"
     2: the quality of being useful and convenient; "they offered
        the convenience of an installment plan" [ant: {inconvenience}]
     3: a toilet that is available to the public [syn: {public
        toilet}, {comfort station}, {public convenience}, {public
        lavatory}, {restroom}, {toilet facility}, {wash room}]
     4: a device that is very useful for a particular job [syn: {appliance},
         {contraption}, {contrivance}, {gadget}, {gizmo}, {gismo},
         {widget}]