Indeterminate vs. Indeterminable – Which is Correct?

While both indeterminate and indeterminable are valid adjectives in English, they convey distinct nuances. Indeterminate refers to something vague, not precisely fixed, or lacking a clear boundary. Indeterminable, on the other hand, describes something that cannot be determined, ascertained, or decided, often due to inherent difficulty or lack of information.

Indeterminate or Indeterminable – Which is Correct?

Both “indeterminate” and “indeterminable” are grammatically correct and widely used in American English, but they are not interchangeable. The core difference lies in their emphasis: indeterminate describes a state of being undefined or unfixed, while indeterminable describes the impossibility of defining or fixing something.

Think of it this way: something indeterminate is currently unclear or not set, but theoretically could be determined. Something indeterminable, however, is fundamentally beyond determination or calculation. For instance, an election result might be indeterminate if votes are still being counted, but the exact number of stars in the universe is likely indeterminable.

The Best Trick to Remember the Difference

To remember the difference, focus on the suffixes:

• The -ate in indeterminate relates to a state or condition. Think of something in an “indeterminate state” – it’s currently unclear or unfixed.
• The -able in indeterminable means “capable of being.” The “in-” prefix negates this, so indeterminable means “not capable of being determined.”

If you can ask, “Can it be determined?” and the answer is “No, it’s impossible to know,” then indeterminable is likely the correct choice. If it’s simply “not yet determined” or “vague,” then indeterminate is more appropriate.

Word	Part of Speech	Meaning	Example
Indeterminate	Adjective	Not precisely fixed, vague, unknown, or left undecided.	The outcome of the complex negotiation remained indeterminate until the very last minute.
Indeterminable	Adjective	Cannot be precisely ascertained, calculated, or decided. Impossible to determine.	Due to the lack of records, the exact age of the ancient artifact was indeterminable.

How to Use Indeterminate

The adjective indeterminate describes something that is not definite, precise, or fixed. It implies a state of being vague, uncertain, or undecided. It often applies to quantities, qualities, times, or outcomes that lack clear boundaries or specific values. The tone is generally formal and objective, often used in scientific, legal, or philosophical contexts.

Example 1: The patient presented with a fever of indeterminate origin, prompting further diagnostic tests.

Example 2: The artistic piece featured an indeterminate number of abstract shapes, inviting individual interpretation.

Example 3: The committee decided to keep the deadline indeterminate for now, awaiting more information on resource availability.

Etymology of the word Indeterminate

The word “indeterminate” comes from the Latin prefix in- (meaning “not”) combined with determinatus, the past participle of determinare (“to limit, fix, determine”). Thus, its original meaning was “not limited” or “not fixed.” It entered English in the late 16th century.

How to Use Indeterminable

The adjective indeterminable describes something that cannot be determined, calculated, or ascertained. It implies an inherent impossibility of reaching a definite conclusion or value, often due to insufficient data, complexity, or a fundamental lack of clarity. Like indeterminate, its tone is formal and objective, frequently appearing in academic or technical discourse.

Example 1: The precise moment of the universe’s creation remains indeterminable by current scientific methods.

Example 2: Because of the extreme erosion, the original inscription on the monument was completely indeterminable.

Example 3: The long-term economic impact of the new policy is still indeterminable given the volatile global market conditions.

Etymology of the word Indeterminable

“Indeterminable” also derives from the Latin in- (“not”) and determinare (“to limit, fix, determine”). The key difference is the addition of the suffix -able (from Latin -abilis), meaning “capable of being” or “fit for.” Therefore, it means “not capable of being determined.” This word appeared in English slightly later than “indeterminate,” around the early 17th century.

Related Concepts

Understanding related linguistic concepts can further clarify the distinct uses of indeterminate and indeterminable.

• Prefixes and Suffixes: The prefix “in-” (meaning “not” or “without”) is crucial to both words. The suffixes “-ate” (often denoting a state or result) and “-able” (meaning “capable of” or “fit for”) are what differentiate their meanings, highlighting whether something is simply in an unclear state or is fundamentally impossible to clarify.
• Modality: These words touch upon the concept of modality, specifically impossibility. Indeterminate suggests epistemic uncertainty (we don’t know), while indeterminable suggests alethic impossibility (it cannot be known).

Examples from Media and Literature

Here are a few examples showcasing the correct usage of these words:

• In a scientific paper, a researcher might write, “The exact number of variables influencing the outcome was indeterminate at the outset of the experiment.”
• A legal document could state, “The court ruled that the amount of damages was indeterminable without further investigation into the claimant’s losses.”
• From a news report on June 2, 2026: “The exact cause of the sudden market fluctuation remains indeterminate as analysts review the data.”
• A philosophical text might ponder, “The true nature of consciousness is often considered indeterminable by purely material means.”
• In a historical account, one might read, “Due to conflicting records, the precise date of the ancient king’s birth is indeterminable.”

Practice Exercises

Choose the correct word to complete the sentence.

1. The artist left the background an __________ blur, allowing viewers to project their own interpretations.
2. Despite extensive archaeological digs, the original purpose of the ancient structure remains __________.
3. The jury deliberated for hours, but the verdict was still __________ by late afternoon.
4. The exact number of galaxies in the universe is so vast that it is widely considered __________.
5. Her expression was so __________ that I couldn’t tell if she was pleased or disappointed.

Answer Key

1. indeterminate
2. indeterminable
3. indeterminate
4. indeterminable
5. indeterminate

Indeterminate Synonyms

Synonym	Definition
Vague	Of uncertain, indefinite, or unclear character or meaning.
Undefined	Not defined or explained.
Uncertain	Not known or established; not definite.
Unspecified	Not stated or determined precisely.
Ambiguous	Open to more than one interpretation; having a double meaning.

Indeterminable Synonyms

Synonym	Definition
Unascertainable	Unable to be discovered or established.
Incalculable	Too great to be calculated or estimated.
Unquantifiable	Unable to be measured or expressed as a quantity.
Immeasurable	Too large, extensive, or extreme to measure.
Inscrutable	Impossible to understand or interpret.

Frequently Asked Questions

Question 1: Can something be both indeterminate and indeterminable?
No, not simultaneously in the same context. If something is truly indeterminable, it means it cannot be determined at all. If it’s indeterminate, it implies it’s currently vague or unfixed, but not necessarily impossible to determine. The former describes an inherent impossibility, the latter a current state of uncertainty.

Question 2: Which word is more commonly used?
“Indeterminate” tends to be more frequently used in general discourse, often describing situations or quantities that are simply vague or not yet decided. “Indeterminable” is used when stressing the impossibility of determination, which is a less common scenario in everyday conversation.

Question 3: How do these words relate to “undetermined”?
“Undetermined” is very close in meaning to “indeterminate,” referring to something not yet found out or decided. Often, they can be used interchangeably. However, “indeterminate” can also describe a quality (e.g., “of indeterminate color”), whereas “undetermined” usually implies a process of finding out that hasn’t finished yet.

Conclusion

Mastering the distinction between indeterminate and indeterminable enriches your vocabulary and precision in communication. Remember that indeterminate describes a state of vagueness or lack of definition, while indeterminable denotes an inherent impossibility of being defined or calculated. By recognizing the subtle but crucial difference in their suffixes, you can confidently choose the correct word for your context. A precise command of such nuanced vocabulary not only enhances clarity but also reinforces your professional reputation as a meticulous communicator.