An industry term for a search engine displaying a title link different from the supplied title tag when it believes another string is more helpful.
Title rewrite is the common SEO label for a search engine displaying a result title that differs from a page’s supplied HTML title. It describes an observed difference. It does not, by itself, explain why the difference happened or establish that the site has received a penalty.
Google has explained that it may use visible headings and other text to produce a more helpful page label. Its documentation identifies problems such as stale, incomplete or repetitive title information. These are useful places to investigate, but do not assume every changed title has the same cause.
The practical task is to reconcile the page’s signals. Compare the live title element, visible primary heading, dates and template text with the displayed result. Determine whether the engine’s wording is actually misleading. If the alternative remains accurate and recognizable, changing a well-written page solely to force exact matching may not be a worthwhile priority.
Takeaway: Investigate misleading or outdated title changes first. A rewrite is a reason to compare evidence, not a reason to repeatedly add keywords or assume that every different headline is harming the business.
Example
An annual training page has been updated for a new year, but its title element still contains the old year while the main heading uses the new one. A search engine might choose the newer heading. The useful repair is to make the page consistently accurate, not to argue that the old title must be displayed verbatim.
What to check
Save the observed title, source title, URL and date before editing. Make one coherent correction when evidence supports it, then reassess after processing. There is no supported title-tag command that guarantees Google will use your exact preferred wording.
For more detail, see An update to how we generate web page titles.