Suffix · forms adjectives/nouns
Forms adjectives meaning "related to" and nouns naming places or collections: dictionary, laboratory.
Written by Bryan López, English teacher · Updated
The suffixes -ary and -ory are variants of the same Latin origin. They create two types of words: 1. Adjectives meaning "relating to" or "of the type of": primary, ordinary, necessary, mandatory. 2. Nouns naming places or collections: laboratory, dictionary, library, factory, dormitory. This is a very frequent suffix in academic and formal vocabulary.
Spanish uses -ario/-orio with the same root, and cognates are plentiful: dictionary = diccionario laboratory = laboratorio dormitory = dormitorio obligatory = obligatorio If Spanish ends in -ario or -orio, the English version almost always ends in -ary or -ory.
An important difference from Spanish: in English the stress moves toward the beginning of the word, and the final -ary/-ory is reduced. Spanish: dic-cio-NA-rio (stress on 3rd syllable) English: DIC-tion-ary (stress on 1st syllable, -ary is a quick "er-ee") laboratory: la-BOR-a-to-ry (EN) vs la-bo-ra-TO-rio (ES) In American English one syllable is sometimes dropped: LAB-ra-tor-ee.
Latin root + ary (French/Latin origin words) or + ory. Many are fixed vocabulary.
The choice between -ary and -ory depends on the original Latin root, not a modern rule. In practice, the most common words are learned directly as vocabulary.
-ary / -ory/əri/ or /ɔːri/ · sounds like 'er-ee' or 'or-ee'
Tap the button to hear how the ending sounds. Each word in the table has its own audio.
library has three syllables: LI-brar-y. It is very common to mispronounce it as "libery" (two syllables).
laboratory = la-BOR-a-to-ry (5 syllables). In American English it reduces to LAB-ra-tor-y (4 syllables). Not "labratory".
necessary: one c at the start, double s in the middle: ne-CES-sa-ry. Trick: "one collar, two socks" = 1c + 2s.
A trick to remember it
If Spanish says -ario/-orio, English says -ary/-ory: diccionario = dictionary, laboratorio = laboratory. And remember: stress shifts forward in English, the ending sounds like a quick "er-ee" or "or-ee".
Exercise 1 · Form the word
Exercise 2 · Pick the right one
How is "library" pronounced?
Exercise 3 · Pick the right one
"temporary" means...
The suffix -ary / -ory forms adjectives meaning "related to" and nouns naming places or collections: dictionary, laboratory. In Spanish it usually maps to -ario / -orio.
The ending -ary / -ory is pronounced /əri/ or /ɔːri/ · sounds like 'er-ee' or 'or-ee'. For example, "dictionary".
"diction-" becomes "dictionary". It is a typical example of the -ary / -ory suffix.
Turns a noun into an adjective meaning "related to" or "belonging to": nation becomes national.
Turns a noun into an adjective meaning "of", "relating to" or "characteristic of": economy becomes economic.
Turns a verb or noun into an adjective showing tendency or capacity: create becomes creative.
-tion, -ness, -ful, -ly, -able... every ending you need to understand thousands of words at once.