Keyword Cannibalisation
Keyword cannibalisation occurs when several pages on the same website are optimised for the same keyword and therefore compete against each other in search results instead of against external competitors. This makes it harder for Google to tell which page is most relevant, which can weaken the ranking performance of every page involved.
In practice
In practice keyword cannibalisation usually happens unintentionally, for example when several blog articles or landing pages on the same topic accumulate over time without a keyword map defining which page owns which search term. The result is often volatile or mediocre rankings, because the pages compete with one another for the same relevance signals. Regular content audits help, as does consolidating overlapping content by merging it, redirecting it or giving each page a clearly different thematic focus.