LSI and Semantic Keywords: What Actually Matters for Topic Coverage
"LSI keywords" is one of the longest-running pieces of SEO folklore. You'll see tools that generate lists of them and freelancers who promise to sprinkle them through your content. The term comes from latent semantic indexing, a document-retrieval technique from the late 1980s. Google has said it doesn't use LSI, and there's no evidence a list of "LSI keywords" does anything special. The idea underneath, though, is right: pages that cover a topic thoroughly and naturally tend to do better than pages that repeat one phrase. That idea is better called semantic coverage, and it's worth getting right.
How Google understands topics today
Modern search engines use language models and an index of entities, things like people, places, products and concepts, and the relationships between them. Google knows that "Jaipur" is a city in Rajasthan, that "Hawa Mahal" is in Jaipur, and that someone searching "things to do in Jaipur" probably wants forts, markets and food as well.
So a page about Jaipur sightseeing that mentions Amber Fort, Nahargarh, Johari Bazaar, entry tickets and the best months to visit looks like a complete answer. A page that says "things to do in Jaipur" fifteen times and mentions nothing specific looks thin. Neither needs a list of magic words. The first simply covers the subject.
Synonyms, related terms and subtopics
It helps to separate three kinds of "semantic" terms.
Synonyms and variants
"Running shoes", "running sneakers", "jogging shoes". Google handles synonyms well, so you don't need to cram every variant in. Use whichever feels natural, and mix them a little.
Related terms
Words that tend to appear when a topic is explained properly. A guide to sourdough will naturally mention starter, hydration, levain, proofing and scoring. If those words are missing, the page probably isn't covering the subject.
Subtopics
The questions a searcher has next. For "how to start a podcast": equipment, recording software, hosting, editing, publishing to Spotify and Apple, getting listeners. Subtopics usually become your H2s.
Of the three, subtopics are where most pages fall short.
Finding the terms worth covering
None of these require paid tools:
- Read the top results. Open the five highest-ranking pages and note the subtopics they all cover. Anything every one of them covers is probably expected.
- People Also Ask. The question boxes in Google show what searchers want to know next. Click a few to expand more.
- Related searches. The suggestions at the bottom of the results page.
- Autocomplete. Type your keyword and add letters (a, b, c) to see variations.
- Search Console. For existing pages, the Queries report shows terms you already get impressions for. If a page ranks at position 15 for a related question it never actually answers, add a section that answers it.
- Your customers. The questions people ask on calls, in WhatsApp messages and in reviews are often the subtopics competitors miss.
Paid content tools can speed this up by comparing your page against top results. They're useful as a prompt, but treat their term lists as suggestions, not a quota.
Writing with semantic coverage in mind
Outline before you write
List the subtopics as headings. If you can't write a decent paragraph under one, either research it or drop it.
Be specific
Specific nouns carry meaning. "Use a good camera" says nothing; "a USB microphone like a dynamic model reduces room echo better than a condenser in an untreated bedroom" uses several related terms precisely because it's explaining something.
Answer the follow-up questions
After each section, ask what the reader would wonder next. That's often the next subtopic.
Use entities correctly
Name the real things: tools, places, standards, regulations. A GST article that mentions GSTR-1, GSTR-3B and the GST portal reads as competent to people and machines alike.
What not to do
- Don't paste in a list of terms. A sentence written to include "best", "cheap", "online" and "near me" helps no one and reads awkwardly.
- Don't chase a density target. There's no ideal percentage, as the keyword density myth explains.
- Don't cover everything on one page. If a subtopic is big enough to deserve its own article, give it one and link to it. This is how topical authority gets built.
A worked example
Say you run a home bakery in Jaipur and want a page on "eggless cakes in Jaipur". A thin version lists flavours and repeats the phrase. A semantically complete version covers: the flavours you make, whether you use gelatin or other ingredients vegetarians avoid, sizes and serving counts, price ranges, delivery areas (Malviya Nagar, Vaishali Nagar, C-Scheme), order lead time, custom message and photo options, and how to order. Every one of those is something a real customer asks. Not one of them came from an LSI tool.
If you want a broader view of how keyword choice fits into this, the keyword research guide is the place to start. For your next article, spend fifteen minutes on the top five results and People Also Ask before writing, and build your outline from what you find.