In brief
HTML mark identifies text highlighted because of its relevance in the current context. A match in search results is a suitable example.
Useful to know
HTML mark identifies text highlighted because of its relevance in the current context. A match in search results is a suitable example. [1]
This differs from general strong emphasis or a merely decorative yellow background. Use mark when there is a reason to point out the passage, and check text contrast against the highlighting colour.
Sources
For further detail and to check the information: