In XML terminology, topic can mean

1. A resource that acts as a proxy for some subject; the topic map system's representation of that subject. The relationship between a topic and its subject is defined to be one of reification. Reification of a subject allows topic characteristics to be assigned to the topic that reifies it.
2. A element, used in many XML formats.

External link

• Specification in XML Topic Maps (XTM) 1.0 (topicmaps.org)

XML