A fyrk was a monetary unit used in Sweden in the 15th to 17th century, with a value of between 1/6 and 1/2 öre. The word is derived from Middle Low Germanvereken (vierichen) and ultimately from ver or vier, a monetary unit (from vier, "four"). After the monetary unit had been abolished, the word remained in use in the general sense of "small money", "pennies", "an insignificant sum"; and as a slang word for "money" in Finnish Swedish as well as in Finnish as a dialectal loan word (fyrkka).
With the Swedish municipal reform 1862, the unit fyrk was re-used as a unit for counting voting rights in the municipal election. Voting rights were graded according to income and assets, counted in fyrks and recorded in the fyrktalslängd, the "fyrk counting list" for each municipality. It was in use from 1863-1909. The vägfyrk or "road fyrk", a unit for road tax, remained in use until 1937.
Materials used to manufacture fyrks was silver and lately also copper.