Text As Instance Across Semiotic Modes

Halliday & Matthiessen (2014: 46):

The term ‘text’ includes both spoken and written instances of the linguistic system. … However, the sense of text is being extended to other semiotic systems, and scholars refer to instances of e.g. ‘visual semiotic’ systems as ‘(visual) texts’ (thus a painting would be a visual semiotic text) and they also refer to ‘multimodal texts’ — instances of more than one semiotic system.