The name could be a Germanized form of Sinya, a Russian diminutive of Euphrosyne. A more likely etymology is that it is from the German contraction of Gesina, the Frisian form of Gertrude, or it may be derived from the Frisian sin (sun). The name has also been sometimes correlated with a Bulgarian source, Sinia, (blue).
Currently, Sinja is the 456th most popular female name in Germany, (2011).
Other forms of the name include: