Is Artificial Intelligence Countable or Uncountable?

In standard English, "artificial intelligence" is an uncountable noun when it names the field or the capability, so it takes no article and no plural: "artificial intelligence is advancing." Dictionaries also record a countable sense for a single system that has the capability, which is why "an AI" and "AIs" appear in print. The countable forms that are least disputed are "AI system," "AI model," and "AI tool."

Key takeaways

Cambridge Dictionary labels "artificial intelligence" as uncountable ([U]) in its learner's, American, and business entries.
A commercial online dictionary lists "AI" with both an uncountable sense (the ability of a machine to perform human-like tasks) and a count sense (a computer, robot, or software application that can do so).
Several major dictionaries could not be read directly for this article, so no claim is made about their labels.
Standards documents avoid the problem by counting systems: the NIST AI Risk Management Framework defines an "AI system."
"An AI" is acceptable in informal writing and in fiction, while formal writing usually prefers "an AI system."

What dictionaries record

The question is a grammar question, and dictionaries are the right place to settle it. Cambridge Dictionary marks "artificial intelligence" with the uncountable label [U] in its learner's, American, and business entries, and defines it as the use or study of computer systems that have some qualities of the human brain, such as the ability to interpret and produce language.

That dictionary is more permissive. Under "AI" it lists an uncountable sense, the ability of a machine or program to perform tasks such as recognizing speech and answering questions, and a separate count sense, a computer, robot, other device, or software application that can perform tasks resembling human learning and decision-making. A third sense covers the branch of computer science concerned with designing such systems. The count sense is what lets writers say "an AI." Merriam-Webster, Collins, and the Oxford English Dictionary block automated access, so their entries were not checked for this article and are not described here.

Why the same words behave two ways

English handles many fields this way. "Medicine," "chemistry," and "physics" name a body of knowledge and do not take articles. The word "intelligence" itself is uncountable when it means the ability to learn, so "artificial intelligence" inherits the pattern when it names an ability or a field. Verbs agree accordingly: "artificial intelligence is," not "are."

The countable sense is recorded separately because a system that has the capability can itself be named by the same words, as in "an AI." Because at least one major dictionary lists that sense, "AIs" is not an error, but it can sound loose in formal prose.

A usage table

Wording	Sense	Fit
Artificial intelligence is used in many fields.	Field or capability, uncountable	Standard in all registers
Some artificial intelligence was added to the app.	Capability, uncountable, with a quantity word	Standard
Three artificial intelligences were compared.	Countable systems, plural form	Follows the count sense; unusual in formal writing
An AI wrote the draft.	One system, countable	Common in informal and journalistic writing
Three AI systems were compared.	Countable noun with a head noun	Preferred in technical and policy writing
The two AI models disagreed.	Countable noun with a head noun	Preferred in technical writing

The table describes recorded usage and a stylistic judgment, not a rule that style guides enforce. Readers who follow a house style guide should check what it says about the term.

How standards documents handle it

Policy and engineering texts usually avoid the countability problem by defining a countable phrase. NIST (National Institute of Standards and Technology), a U.S. agency, issued the AI Risk Management Framework as NIST AI 100-1, version 1.0, in January 2023. Its definition of an AI system is functional: an engineered or machine-based system that, for a given set of objectives, can generate outputs such as predictions, recommendations, or decisions influencing real or virtual environments. The framework adds that AI systems are designed to operate with varying levels of autonomy, and the definition is marked as adapted from the OECD Recommendation on AI (2019) and ISO/IEC 22989:2022.

The definition lets writers count: one AI system, five AI systems. Such definitions give technical texts a countable noun without relying on the looser sense.

Practical guidance for writers

Use "artificial intelligence" without an article for the field or capability.
Use "AI system," "AI model," or "AI tool" when a number or an article is needed.
Reserve "an AI" for informal prose, dialogue, and fiction.
Match the verb to the head noun: "artificial intelligence is," "AI systems are."
Keep one choice within a document so that the reader does not wonder whether the terms differ.

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