What Are Semantic Keywords?
Semantic keywords are words and phrases that are topically related to your main subject. If your page is about "running shoes," terms like trainers, sneakers, cushioning, gait analysis, marathon, and pronation are semantic keywords. They signal to search engines and AI engines that your page covers the topic with real depth instead of just repeating one phrase. An Ahrefs study found the average top-ranking page also ranks for around 1,000 related keywords — because it covers the topic, not just one keyword.
You may see the term "LSI keywords" used interchangeably. LSI stands for Latent Semantic Indexing, a 1988 algorithm from Bell Labs (Deerwester et al.). Google's John Mueller has publicly stated Google does not use that specific math — modern engines use BERT, MUM, and word embeddings instead. But the underlying principle is identical: broad, semantically-related vocabulary signals topical relevance, and that is exactly what modern systems reward. This metric is part of the Content Quality pillar in your GEO-Score.
How Semantic Search Actually Works
intro
Understanding why semantic keywords matter requires knowing how modern search engines process text. The technology has evolved dramatically from simple keyword matching.