Compositional etymology where ἀσφαλής provides the ψ, through a metathesis [sph] > [phs] > [ps], and ὄχημα the [khē]. An evolution *σφ-οχή > *ψοχή > ψυχή may be assumed, since the change of [o] to [u] was a familiar device for Greek etymologists, who assumed the change was characteristic of Aeolic. The soul is the vehicle of the mind (ibid., l. 143 Ψυχὴ δὲ πρῶτα νοῦν τε καὶ λόγον φέρει), this is why it is etymologized by ὄχημα