The story
The name of Sievi is derived from the word sievä, which in the local dialect means "smooth". The name was in reference to an esker on which the farm of Sievi(lä) was located. Said farm was first mentioned in 1547 and was owned by Olli Ollinpoika Hihna. Sievi was a part of the Kalajoki parish, under which it became a chapel community in 1645. The chapel community was also known as Evijärvi (not to be confused with the Southern Ostrobothnian Evijärvi) after another village in the area, which is nowadays known as Järvikylä. After becoming an independent parish and municipality in 1862, Sievi became the only official name for it.
From Wikipedia’s article on Sievi, shared under CC BY-SA 4.0.5