Volk (in this sense) really means People, in the same way the term for themselves used by almost every native tribe in the world means People or The People.
The implication of course, by both the tribes and the Germans, was that other people weren't really people at all.
The volkisch movement is rooted in the German Romanticism of Goethe, Arndt, Schopenhaeur and Riehl, which was later undergirded by Ernst Haeckel’s Social Darwinian ecological ‘science.’ Heidegger’s existentialism, borrowing from some of his own cadre of racist folks, emphasized the enemy otherness of the volkisch movement and placed it on a philosophical basis rather than upon biology or ecology. Yet Heidegger is still considered a who’s who of Nazi environmentalism. Heidegger’s racism, therefore was still rooted in the German soil, but was based on ontology and not upon the scientism of Nazi science. The entire crowd listed above loved nature and were anti-Semitic in varying degrees, and Nature was used as the justificaiton for their racism.