Use page search for text in the currently open Safari webpage, and ordinary search for the web. First identify the document you intend to check: the same phrase can produce different counts in different scopes.
Search the current webpage
With the target page open, open Safari’s Page Menu and choose “Search Document,” then enter the word or phrase. Apple describes this control as a way to find text in a webpage, while entering a term in the search field performs a web search. The exact wording or location may vary with the installed version, so consult Apple’s Safari page-search instructions if the interface looks different.
Search the spelling visible on the page. In this example it is duration. Searching “time” instead asks a different question; a zero result for that substitute does not establish that duration is absent.
A worked comparison of search scope
Hypothetical example: suppose the currently open Safari page contains duration twice. It also links to a separate appendix, where the same word appears once. Searching the current document returns 2 matches, not 3.
The comparison is: current page, 2 matches; separate appendix, 1 match; both documents counted together, 3 matches. That combined total is not the result for the current page. After you open the appendix, it becomes a different document and must be searched separately. Page search answers how often the phrase appears in the open webpage, not how often it appears across a whole site.
What zero matches means
If no match appears, check the exact spelling, spaces, hyphens, and compound form shown on the page. Confirm that the intended webpage is still open. A zero result means that Safari did not find that input in the current search scope. It does not prove that the entire website lacks the topic, or that another article or linked appendix lacks the term. Open that document and search again. Use ordinary web search only when your goal is to look beyond the current page.