Abstract: Research on structural colour tends to focus on understanding the nanostructure that generates the colour, rather than the appearance of the colour itself. The topic is generally covered from a technical perspective, where the visuality and aesthetics of the colour remain out of focus. As a result, a limited toolbox of unclear terminology limits both the description of the wide range of visual features of, and the design potential of structural colour. In the absence of established and widespread definitions, users of structural colours may encounter misunderstandings and misinterpretations of the appearance of structural colour. In essence, the visual features are usually oversimplified with too broad terms, such as "iridescent," "shiny and glittery," or "metallic". These function well as umbrella terms, but more specific descriptions of the visual qualities are needed. This work provides a coherent overview and explanation of the varied terminology used both in scientific and colloquial contexts. A major scrutiny is provided for 1) the visuality of iridescence, 2) the borderline between pigment colours and structural colours, as well as 3) the varied terminology used for effect pigments. In order to cover the technical perspective, a brief and easily available information package is provided on the classification of structural colour based on the structures and related mechanisms that bring about the colour. Finally, a table is introduced which proposes more detailed descriptions of the wide range of the visual qualities of structural colour. It is envisioned to advance the exchange of information between disciplines, to benefit both research on structural colour and end users of these colours, like designers and artists.