The article is dedicated to the problem of phonosemantic elements in the lexis functioning in languages for special purposes. The concern about inoccurence of phonosemantic words suggests the idea of their limited use and, in particular, their limited performance only in expressive layers of the language. The heuristic potential of phonosemantics gives the ground for hypothesizing the existence of this phenomenon in subsystems standing far from the expressiveness – in terminology which constitutes the core of the language for special purposes, and in the sphere of professional jargons.