This paper elaborates on an approach to the cross-linguistic comparison of lexical (sub)systems, which is based on the differentiation of typologically relevant semantic domains. We illustrate this approach exploring the conceptualization of motion / being in liquid medium (aqua-motion), within which four general domains (SWIMMING, SAILING, DRIFTING and FLOATING) are recognized. Using this distinction, we propose a typology of aqua-motion systems that distinguishes between ‘rich’, ‘poor’ and ‘middle’ systems of aqua-motion expressions depending on the lexical contrasts that the language displays.