Semantic Search
Semantic search is the shift from matching keyword strings to understanding meaning, context and relationships between concepts. It is why a page can rank for a phrase it never uses, and why synonyms and related topics now carry real weight.
Why it matters for your rankings
Semantic search ended keyword-matching as a strategy. Google's systems understand that crawl budget relates to indexing and server capacity without those words appearing near each other, because it models concepts rather than strings.
The practical consequence is that comprehensive coverage beats repetition. A page addressing a subject and its adjacent questions outranks one that repeats a target phrase, even if the second contains the exact wording. It also means content written naturally for people performs better than content engineered for algorithms, which was not reliably true fifteen years ago. For AI answer engines this matters more still, since they reason over meaning and cite passages that state ideas clearly.
How to check it on your site
Map the concept, not the keyword
List the questions and subtopics a knowledgeable person would expect covered, then check your page addresses them.
Study what already ranks
The subtopics common to the top results indicate what Google considers part of the concept.
Use natural language
Write with synonyms and varied phrasing. Engines handle this well and readers prefer it.
Link related pages together
Internal links between conceptually related pages reinforce the relationships engines are modelling.