In practice
There is no such thing as an “LSI keyword” in modern search. What people mean by it — covering a topic with the vocabulary it naturally uses — is sound advice under the wrong name.
Plan coverage from real queries and entities instead of buying lists of supposedly semantic terms.
Why it matters
The term persists in old guides and still sells tools that measure nothing Google uses.
Knowing the history keeps a content brief focused on intent rather than on word lists.
Related terms