This is a Swedish surname from the 18th century. Recorded in various spellings including Sellstrom, Sahlstrom and the rare Sellgstrom, it is of a group known as "ornamental". In that respect it has some simularity with the (mainly) British or German double barrelled surnames, where two entirely separate elements of individual origins and meanings, are brought together to form a distinctive new name. This new name has no specific meaning except that two families have joined together for whatever reason, although sometimes over centuries the merger has been known to create its own identity. In this case the origins are the names Sell, Sells or Zell, possibly from the original Latin "cella" meaning a shelter, and the pre 7th century Olde Norse word "straumer", the later Swedish surname "Strom" meaning a river. There are a number of similar names including Sellgren (shelter green), Sellmar (shelter marsh), or reversing the formula Strombach (river stream), or Stromblom (river tree). The growth of ornamental surnames in Scandanavia was encouraged by the various governments of the time, as the original surnames were highly limiting in number and scope, being almost all patronymics such as Anderson, Larson, and Johansson. Like Wales and to some extent Scotland, this lead to whole areas having the same name, and therefore defeating the purpose of identification. Early examples of this surname recorded in the church registers of the town of Gefle, include Johan Sellstrom who married Magdalena Sten on November 26th 1742, and Anders Sahlstrom who married Ulrika Asp on September 18th 1793.