The Collaborative International Dictionary of English v.0.48:

kopeck \ko"peck\, n.; pl. Eng. kopecks, Russ. kopeek. [Russ.
   kopeika.]
   A small Russian coin, continued as a unit of currency within
   the Soviet Union. One hundred kopecks make a ruble. The ruble
   was worth about sixty cents (U. S.) in 1910; in 1991 a
   two-kopeck coin could be used for a local telephone call at a
   pay telephone. After the breakup of the Soviet Union in 1993,
   the exchange value of the ruble declined rapidly and by the
   end of 1994 the ruble was worth three hundredths of a cent,
   and by 1997 two hundredths of a cent. By 1993, the kopek had
   become of such small value that it was obsolete and no longer
   minted. [Written also kopek, copec, and copeck.]
   [1913 Webster] kopje

WordNet (r) 3.0 (2006):

kopek
    n 1: 100 kopecks equal 1 ruble in Russia [syn: kopek,
         kopeck, copeck]