The element of severity remains core to the definition and interpretation of torture under international law. It has long represented a source of confusion and obfuscation for the legally-oriented anti-torture professional, whether academic, advocate or adjudicator. Its character as decisive differentiator, setting torture apart from cruelty, inhumanity and degradation, remains problematically entrenched and contested. It is a legal construct not finding its origins in the scholarship on pain, and evades precise measurement – as pain is socio-culturally constructed, relative and subjective. Accepting the prevailing complexity and addressing the perennial ambiguity, this article aims to offer some clarifications towards conceptualising and contextualising, and thereby better specifying and applying, torture’s core.