a priory (a priori)

Writers often write or say "a priory" when they mean the Latin phrase "a priori." One is a monastery; the other means "prior to experience" or "by deduction." Use a priori for reasoning and a priory only when you mean the religious house.

Quick answer: which is correct?

Use a priori when you mean reasoning or knowledge independent of experience; use a priory only when you mean a monastery or convent.

a priori = "independent of experience," used in philosophy, law, and formal argument.
a priory = a priory (a monastery or convent); not a substitute for a priori.
If unsure, try replacing the phrase with "by deduction" or "independently of experience"-if the sentence still makes sense, a priori is right.

Core explanation: what a priori means

a priori is Latin for "prior to experience." It describes conclusions drawn from logic or theory rather than from observation or data.

Grammatically, it usually modifies a claim (adverb: "This is a priori unlikely") or a noun (adjective: "an a priori assumption").

Meaning: independent of empirical evidence; derived by reasoning.
Form: two words, typically lowercase in running text.

The mistaken phrase: why writers type a priory

The confusion comes from similar sounds and the visual link to "prior" or words ending in -ory. But the meanings are unrelated: priory is a place; priori is a phrase about reasoning.

Sound-alike trap: priory vs. priori look and sound similar.
Check meaning: if the sentence refers to a place, priory may be correct; if it refers to reasoning, use a priori.

Wrong: Her hypothesis was a priory, so she dismissed the contrary data.
Right: Her hypothesis was a priori, so she dismissed the contrary data.
Wrong: The young novices spent their days at a priory tending the garden. (Correct because it refers to a monastery.)

Grammar: form, articles, and capitalization

Write a priori as two words. Keep it lowercase in running text unless it starts a sentence. Use "an" before it when that reads smoothly ("an a priori argument"), though "a priori evidence" is also common.

Correct: a priori (two words), lowercase in body text.
Article: choose the article that reads naturally and stay consistent.
Function: treat it as a modifying phrase, not an English noun.

Usage: An a priori objection to the method is that it ignores user behavior.
Usage: A priori, we assumed the sample would be random.

Hyphenation and spacing: avoid these traps

Never collapse a priori into one word (apriori) and never hyphenate it (a-priori). Both are nonstandard. Only use a priory if you mean the monastery.

Correct: a priori
Incorrect: apriori, a-priori, a priory (unless meaning monastery)
If autocorrect keeps changing it, add a priori to your dictionary rather than accepting the wrong form.

Wrong: apriori
Wrong: a-priori
Right: a priori

Real usage and tone: when to keep the Latin

Keep a priori in formal writing-philosophy, theoretical science, legal reasoning-where the Latin adds precision. For general audiences, prefer plain phrases like "by deduction," "without empirical evidence," or "based on theory."

Formal contexts: retain a priori for accepted terminology and precision.
General audiences: use plain language to avoid sounding pedantic.
Tone test: if "without data" or "by logic" preserves meaning, pick the plain form.

Work (formal): We cannot claim market-fit a priori; we need customer interviews.
Work (slide): Assumption (a priori): user preference is stable across segments.
Work (executive): We cannot assume this will work without evidence.
School: An a priori justification for mathematical truths contrasts with empirical claims.
Casual: Not sure we can say that before seeing the data.

Try your own sentence

Test the whole sentence, not the phrase in isolation. Context usually makes the correct choice obvious.

Examples and rewrites: wrong/right pairs and ready rewrites

Below are common mistakes with clean corrections and simpler rewrites you can copy into your draft.

Wrong: The judge dismissed the claim on the grounds that it was a priory improbable.
Right: The judge dismissed the claim on the grounds that it was a priori improbable.
Wrong: We concluded a priory that the model would generalize to all markets.
Right: We concluded a priori that the model would generalize to all markets.
Wrong: Her a priory belief caused her to discount the survey results.
Right: Her a priori belief caused her to discount the survey results.
Wrong: On an a priory basis we can rule out external causes.
Right: On an a priori basis we can rule out external causes.
Wrong: The analyst said a priory assumptions were baked into the forecast.
Right: The analyst said a priori assumptions were baked into the forecast.
Wrong: It would be a priory rash to implement that policy without pilot data.
Right: It would be a priori rash to implement that policy without pilot data.
Wrong: They assumed a priory that users prefer the feature.
Right: They assumed a priori that users prefer the feature.

Rewrite:
Original: "We concluded a priori that uptake would be high." → Simpler: "We assumed uptake would be high, but we need data to confirm."
Rewrite:
Original: "Her a prior(y) stance ignored evidence." →
Correct: "Her a priori stance ignored evidence." → Simpler: "She ignored the evidence because she assumed it was true."
Rewrite:
Original: "On an a priory basis, the result is unexpected." →
Correct: "On an a priori basis, the result is unexpected." → Simpler: "Based on theory alone, the result is unexpected."
Rewrite:
Original: "That's a priory incorrect." →
Correct: "That's a priori incorrect." → Simpler: "That's clearly incorrect."
Usage tip: Before sending to nonacademic recipients, replace "a priory" with "a priori" or a plain phrase like "based on theory."

How to fix your sentence: a short editing checklist

Use this quick checklist whenever you spot a suspect phrase.

1) Ask: does the sentence mean "monastery" or "logical deduction"?
2) If deduction, replace "a priory" → "a priori".
3) Consider audience: for general readers, replace a priori with "by deduction," "based on theory," or "without empirical evidence."
4) Read the sentence aloud; if it sounds stilted, use the plain-language rewrite.

Fix: "The policy is a priory flawed." → "The policy is a priori flawed." → Plain: "The policy is flawed in principle."
Fix: "We thought a priory that the feature would be adopted." → "We thought a priori that the feature would be adopted." → Plain: "We assumed the feature would be adopted without testing."
Fix: "a priory assumptions" → "a priori assumptions" → Plain: "assumptions made in advance."

Memory tricks and quick checks to avoid the error

Priory → place mnemonic: words ending in -ory (factory, library) are places, so "priory" is a place.
Priori → "prior to experience" mnemonic: think "prior" + "i" to remember "prior to experience."
Add a priori to your spellchecker; set a rule that flags "a priory" and asks you to check meaning.
Substitution test: replace the phrase with "by deduction" or "without empirical evidence"-if it still works, a priori is appropriate.

Similar mistakes worth watching

Watch for other Latin or near-homophone confusions while you edit.

a priori vs. a posteriori - opposites: a posteriori means "after experience" (based on evidence).
prior vs. priority vs. priori - "prior" and "priority" are English words; they are not the Latin phrase.
apriori and a-priori - nonstandard spellings; avoid them and use "a priori."

Usage: Compare: "We accept it a posteriori-because our tests confirmed it-rather than a priori."
Usage: Wrong: "apriori we assume..." →
Right: "a priori, we assume..." or simpler: "We assume this in theory."

FAQ

Is a priory the same as a priori?

No. a priory is a monastery. a priori means "independent of experience" and is correct when you mean logical deduction or theoretical reasoning.

Should I write "an a priori" or "a a priori"?

Many writers use "an a priori" because it begins with a vowel sound; "a priori" also appears. Choose the article that reads smoothly and be consistent.

Is apriori one word or two?

Write it as two words: "a priori." The single-word "apriori" and the hyphenated "a-priori" are nonstandard.

When should I use a priori versus plain language?

Use a priori in formal, academic, or legal contexts where the Latin adds precision. For general audiences, use plain alternatives like "by deduction," "based on theory," or "without empirical evidence."

How can I stop my editor from autocorrecting to a priory?

Add "a priori" to your editor's dictionary and create a replacement rule that flags "a priory" and suggests "a priori" or prompts you to check the meaning.

Quick pre-send checklist

Before you send or publish: search your document for "priory", "apriori", and "a-priori". Replace incorrect instances with "a priori" or a plain-language alternative depending on your audience.

If you write for mixed readers, add a short style note: "Use a priori in academic contexts; otherwise use plain language."