A distinguishable thing, such as a person, organization, place, product or concept, that can be described and connected to other things.
An entity is the thing being discussed, rather than just the words used to name it. Two organizations can share a name, and one organization can have several trading names. Good content supplies enough context for a reader to tell which one is meant without guessing.
For a business website, that may involve a clear company description, accurate contact information, an identifiable owner or organization and links to genuine official profiles. The goal is a coherent account of the business. Repeating a name across hundreds of unrelated pages does not make that account clearer.
Structured data can describe identities and relationships in a machine-readable form, but it should reflect visible, verifiable information. There is no need to claim that every business has a complete or permanently unified Google entity record. Search systems and other applications can interpret information differently.
Takeaway: Make it easy to identify who a page is about and how that person, product or organization relates to the business.
Example
Two companies are called Summit Design. One sells furniture and the other designs websites. Each homepage explains its services and location and links to its own official profiles, reducing confusion without pretending the shared name is unique.
What to check
Check for conflicting business names and outdated profile links. Use identity references only when they describe the same entity, not a partner, competitor or broadly related subject.
For more detail, see Google: Organization structured data.