Entity
An entity is a single, identifiable thing: a business, a person, a place, a product, a concept. It is distinct from the words used to name it, so that two businesses with the same name are two entities and one business with three spellings of its name is one.
A thing, not a string
A search engine or an assistant that only matched strings would treat “Smith Plumbing”, “Smith Plumbing Ltd” and “Smiths Plumbing” as three different sources, and would confuse either with an unrelated Smith Plumbing in another country. Working with entities means resolving the strings to the thing: this page, this phone number, this address, this set of reviews all belong to one business. The resolution is what lets an answer combine a phone number from one page, opening hours from another and a review from a third, and attach all of them to the right business.
How a machine confirms which one
It looks for agreement. Schema.org’s root type, Thing, gives every entity a name, a description, a url and an identifier, and its sameAs property points at a reference page that unambiguously identifies the same thing elsewhere: a Wikipedia article, a registry entry, a profile on a platform the machine already knows. When the name on the page, the name in the JSON-LD, the address in both and the profiles linked by sameAs all describe one business, the machine can be confident which entity it is reading about. When they disagree, it has to guess, and it may guess a different business or decline to name any.
A common question
How does a machine decide that three spellings of a name are one business?
It looks for agreement across everything it can read. The schema.org root type gives an entity a name, a description, a url and an identifier, and its sameAs property points at a reference page that already identifies the same thing, such as an encyclopedia article, a registry record or a profile the machine knows. When the name in the prose, the name in the structured data, the address in both and the linked profiles all describe one business, the resolution is settled. When they disagree, the machine guesses, and it may guess a different business or decline to name one.
Related terms
Sources
Entity properties: schema.org, Thing and schema.org, sameAs. No figures on this page.