Abstrakt
Although denotation "siela" might serve as a general expression for an immaterial essence of a human being, it probably has its own more specific meaning among other such expressions. According to D.
Senvaitytė, siela would most likely correspond to English "soul" while for e.g. dvasia "spirit" would fit as a better translation. As in Lithuanian, there are also in Latvian more expressions for this kind of substance than in Slavic languages, nevertheless, in Lithuanian siela we might see direct Indo-European heritage connected to perhaps something like a source of life force.
Etymological explanation offered by R. Kregždys might lead us to such direction, especially when considering possible semantics from Slavic folklore.
The paper contributed thus on understanding this expression from the point of view of Balto-Slavic context.