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Suffix · forms adjectives

-ory

From Latin "-orius/-orium": forms adjectives meaning "relating to" or "serving for," and nouns for places/instruments. Mandatory, laudatory, contradictory, purgatory, oratory, dormitory, promontory.

In Spanish: -orio / relativo aLiterary

Written by Bryan López, English teacher · Updated June 2026

What this suffix does

-ory comes from Latin "-orius" (adjectives: relating to, serving for) and "-orium" (nouns: place for). It entered English via Old French and produces: ADJECTIVES: mandatory (of mandate), laudatory (of laud/praise), contradictory (of contradiction), promissory (of promise), preparatory (of preparation), inflammatory. NOUNS (place for): dormitory (place for sleeping), auditorium (place for hearing), oratory (place for prayer/speaking), laboratory (place for labour/work), conservatory (place for conserving/growing).

Mandatory, laudatory, promissory: the formal register

These -ory adjectives belong to the formal, legal, and literary register of English: "mandatory" = compulsory, required by law or rule. "mandatory attendance." Very common in formal and official English. "laudatory" = expressing praise. "a laudatory review." "laudatory remarks." C1. "promissory" = containing a promise. "a promissory note" (a financial instrument). Legal register. "preparatory" = serving as preparation. "preparatory school" (= prep school). "contradictory" = mutually contradictory, impossible to both be true. "contradictory statements."

Purgatory and oratory: beyond the literal

"purgatory" = in Catholic theology, the state of purification after death. From Latin "purgare" (to purge/cleanse) + -ory. In literary and everyday English, "purgatory" is used metaphorically for any prolonged state of suffering: "waiting six hours in the airport — it was purgatory." "the bureaucratic purgatory of visa applications." "oratory" = 1) a small private chapel; 2) the art of public speaking (from Latin "orare" = to speak). "a master of oratory." "His oratory moved the crowd." These metaphorical extensions show how -ory words move from theological/institutional to everyday discourse.

How it is formed

Latin root + ory. Produces adjectives (relating to) or nouns (place/instrument for).

  • adjective: relating to / serving formandat- = mandatory · laud- = laudatory · contradict- = contradictory · promiss- = promissory · preparat- = preparatory · inflamm- = inflammatory
  • noun: place fordormir- (sleep) = dormitory · audit- (hear) = auditory/auditorium · laborat- (work) = laboratory · conservat- = conservatory · orat- (speak) = oratory
  • noun: literary/theologicalpurgat- (purge) = purgatory · promontori- = promontory · trajectori- = trajectory · categori- = category

In British English: "laboratory" = /ləˈbɒrətri/ (stress on second syllable). In American English: /ˈlæbrətɔːri/ (stress on first). This is one of the most famous British/American pronunciation differences.

How it is pronounced

-ory/ɔːri/ · rhymes with glory

Tap the button to hear how the ending sounds. Each word in the table has its own audio.

Examples

Base word
With -ory
In a phrase
  • mandatemandatoryWearing a helmet is mandatory for all cyclists on this road.
  • laud (praise)laudatoryThe director received laudatory letters from fans around the world after the premiere.
  • promisepromissorya promissory note signed by both parties
  • contradictcontradictoryThe two witnesses gave contradictory accounts of what happened that night.
  • purgepurgatorysix hours in the airport: sheer purgatory
  • preparepreparatoryShe spent weeks doing preparatory research before writing her thesis.
  • orate (speak)oratoryHis powerful oratory moved the crowd and changed many minds that evening.
  • dormir (sleep)dormitoryThe university dormitory where she lived was only five minutes from her class.
  • audit (hear)auditoryChildren with strong auditory memory often find it easier to learn new languages.
  • promonto- (headland)promontorya rocky promontory above the sea

Common mistakes

laudatory = derogatory (both end in -atory)
laudatory = expressing praise (positive); derogatory = expressing disrespect (negative)

"laudatory" = praising, complimentary: "laudatory remarks about her work." "derogatory" = disrespectful, belittling: "derogatory comments." They are near-antonyms. Both end in -atory but have opposite meanings. Very common confusion.

mandatory = recommended (strong suggestion)
mandatory = compulsory, legally required, not optional

"mandatory" = required by law, rule, or authority. Not optional. "mandatory sentencing" = the judge must apply the sentence, no discretion. "Mandatory evacuation." This is much stronger than "recommended" or "advised."

A trick to remember it

-ory = relating to (adjectives) or place for (nouns). Key adjectives: mandatory (compulsory), laudatory (praising), contradictory. Key nouns: dormitory (sleeping), laboratory, purgatory (suffering). "Laudatory" (praise) vs. "derogatory" (insult).

Practise what you learned

Exercise 1 · Pick the right one

"Laudatory" and "derogatory" are...

Exercise 2 · Form the word

Compulsory, required by law: ___ory

Hint: from Latin "mandatum" (command)

Exercise 3 · Pick the right one

How is "laboratory" pronounced in British English?

Frequently asked questions

What does the suffix -ory mean in English?

The suffix -ory from Latin "-orius/-orium": forms adjectives meaning "relating to" or "serving for," and nouns for places/instruments. Mandatory, laudatory, contradictory, purgatory, oratory, dormitory, promontory. In Spanish it usually maps to -orio / relativo a.

How do you pronounce -ory?

The ending -ory is pronounced /ɔːri/ · rhymes with glory. For example, "mandatory".

Can you give an example of a word with -ory?

"mandate" becomes "mandatory". It is a typical example of the -ory suffix.

Other useful suffixes

  • -age

    Names a collective action, process or result: dam becomes damage.

  • -ery / -ry

    From Old French "-erie": forms nouns of activity, place, collective quality or state. Chivalry, trickery, wizardry, bravery, mockery.

  • -ian / -ean

    Turns proper nouns into style or period adjectives: Orwellian = relating to Orwell's ideas of surveillance and totalitarianism.

Learn every English suffix

-tion, -ness, -ful, -ly, -able... every ending you need to understand thousands of words at once.

View all suffixes
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