prime
prime — adjective
- primepositive
- primercomparative
- primestsuperlative
1. ranking above all others in importance, value, or influence — for example, the p
ranking above all others in importance, value, or influence — for example, the prime reason for a decision or a person's prime concern in a difficult situation.
The prime reason for the project delay was a lack of funding.
prime + reason (attributive use showing main cause)
Ezra's prime concern during the storm was his family's safety.
prime + concern for something that matters most
Reducing child poverty remains a prime objective for the government.
Stefan's prime motivation for learning Mandarin was to communicate with his wife's family.
- prime reason
- prime concern
- prime objective
- prime target
- prime candidate
Grammar Patterns
prime + noun
Usage Note
This sense is almost always used before a noun (attributive). You would not say 'This reason is prime' — instead say 'This is the prime reason.'
Common Mistakes
2. having the highest standard of excellence or the best grade available on the mar
having the highest standard of excellence or the best grade available on the market — used especially for food, materials, and land.
The restaurant serves only prime cuts of beef from local farms.
prime + cut (quality grade of meat)
Camila bought a prime piece of land near the river for her vineyard.
prime + piece of land (best location)
Tara picked the prime spot on the beach, right by the water.
The hotel occupies a prime location in the city centre, near all the main museums.
prime location — common real-estate collocation
- prime cut
- prime beef
- prime real estate
- prime location
- prime spot
- excellent
broader meaning, not limited to commercial grading
- top-quality
more informal; used in advertising and casual speech
- premium
suggests higher price as well as higher quality
- inferior
lower in quality or grade
- substandard
below the expected level of quality
Grammar Patterns
prime + noun
Usage Note
Common in shopping, real estate, and food-industry contexts. 'Prime real estate' refers to land in the best location, and 'prime beef' refers to meat graded as top quality.
Common Mistakes
3. (of a whole number larger than 1) having no whole-number divisors other than 1 a
(of a whole number larger than 1) having no whole-number divisors other than 1 and itself — for instance, 7 can only be split into 1 × 7.
The number 7 is prime because no smaller number divides it evenly except 1.
is prime — predicate use after linking verb
Rin learned to list all prime numbers between 1 and 50 in maths class.
prime number — attributive before noun
Sahil's maths teacher asked the class to circle all the prime numbers on the worksheet.
prime number — attributive use in classroom context
Zola showed her younger brother that 7 is a prime, because nothing except 1 and 7 divides it.
is a prime — noun predicate in informal teaching
- prime number
- prime factor
- prime and composite numbers
- composite
having factors other than 1 and itself
Grammar Patterns
prime number/number is prime
Usage Note
Unlike the other adjective senses, this one can be used both before a noun (a prime number) and after a linking verb (the number 7 is prime).
Common Mistakes
prime — noun
- primesingular
- primesplural
1. the period in a person's life when they are at their peak in terms of physical s
the period in a person's life when they are at their peak in terms of physical strength, energy, health, or professional success.
Professional athletes often reach their physical prime in their mid-twenties.
reach one's prime — verb + noun collocation
Rachid was an outstanding violinist in his prime, touring concert halls across Europe.
in one's prime — fixed prepositional phrase
The photographer captured Maja in the prime of her career as a fashion model.
Bilal retired from competitive swimming while still in his physical prime.
in one's prime — fixed phrase with possessive
- in one's prime
- past one's prime
- prime of life
- prime of career
- reach one's prime
- peak
more general; can also apply to non-human things like performance or demand
- heyday
more literary; suggests a past golden period
- golden age
broader; can refer to a civilisation or field, not just an individual
- decline
the period after one's prime when abilities fade
Grammar Patterns
in one's prime
past one's prime
Usage Note
Used mainly in the fixed phrases 'in one's prime', 'past one's prime', and 'the prime of [someone's] life/career'. Rarely used alone without a possessive or a modifying phrase.
Common Mistakes
2. the written symbol (′) that follows a number or letter, indicating feet in lengt
the written symbol (′) that follows a number or letter, indicating feet in lengths, minutes in angles or timekeeping, or marking a related character as different from the original.
The room measured 12′ by 15′, which means twelve feet by fifteen feet.
′ symbol = feet — measurement notation
In the formula, a′ represents the new value after the calculation.
′ symbol = derivative or second version
The architect wrote 'ceiling height 10′' on the plan, meaning ten feet.
In calculus class, f′(x) is read as 'f prime of x' and stands for the derivative.
f′(x) notation — read as 'f prime of x'
- prime symbol
- prime mark
- single prime
Grammar Patterns
[number]'
[letter]'
Usage Note
Distinguish from the double prime (″) used for inches or seconds. In casual writing, a straight apostrophe (') is often used instead of the proper prime symbol (′).
3. a whole number greater than 1 that can be divided exactly only by 1 and itself.
a whole number greater than 1 that can be divided exactly only by 1 and itself.
The numbers 2, 3, 5, 7, and 11 are all primes because each one has exactly two factors.
primes — noun plural for prime numbers
Tomás had to list every prime under 100 for his homework assignment.
Mathematicians have been trying to find patterns in the distribution of primes for centuries.
distribution of primes — specialist maths collocation
Bilal had trouble remembering which numbers under 30 were primes during the test.
- a prime
- list of primes
- prime distribution
- twin primes
- prime number
the full form; more explicit in educational contexts
- composite number
a number with factors other than 1 and itself
Grammar Patterns
a prime
the primes
Usage Note
Often used interchangeably with 'prime number' in mathematical contexts. The shortest prime is 2, which is also the only even prime.
Common Mistakes
prime — verb
- primepresent simple I / you / we / they
- primes3rd person singular
- priming-ing form
- primedpast simple
1. to give someone information, instructions, or warnings ahead of time so that the
to give someone information, instructions, or warnings ahead of time so that they are ready to handle a particular situation well.
The press secretary primed the journalists with prepared answers before the briefing.
prime + person + with + information
Niran primed his younger sister on what to say during the college interview.
prime + person + on + topic
The team was well primed for the debate after weeks of research.
passive: be primed for + situation
The agent primed the actress for the interview with a list of likely questions.
- prime someone for
- prime someone with
- well primed
- primed to answer
Grammar Patterns
prime + person + for + situation
prime + person + with + information
Usage Note
Often used in the passive ('be primed') or followed by 'with' (information) or 'for' (a situation). The focus is on mental or verbal preparation, not physical training.
Common Mistakes
2. to cover a surface such as wood, metal, or plaster with a first layer of special
to cover a surface such as wood, metal, or plaster with a first layer of special paint or coating that prepares it for the final colour.
Before painting the wall, Lucas primed it with a white undercoat.
prime + surface + with + undercoat
The carpenter primed the wooden door to seal it against moisture.
You should always prime bare metal before applying the top coat.
prime bare metal — typical collocation
After sanding the table, Stefan primed the surface before painting it dark blue.
- prime the wood
- prime the wall
- prime with primer
- prime before painting
- prime and paint
Grammar Patterns
prime + surface
prime + with + primer
Usage Note
Common in DIY and professional painting instructions. The special paint used in this step is called 'primer' (noun). Most surfaces need priming before the final paint will stick properly.
Common Mistakes
3. to load the firing mechanism of a bomb, mine, or gun so that it can be discharge
to load the firing mechanism of a bomb, mine, or gun so that it can be discharged or set off at the right moment.
The soldiers primed the explosives and moved to a safe distance.
prime + explosives — standard military collocation
Eitan carefully primed the old rifle before taking aim at the target.
The device was primed to detonate as soon as the door opened.
passive: be primed to + verb (detonate/explode)
The technician primed the detonator and connected it to the timing mechanism.
- prime a bomb
- prime explosives
- prime a rifle
- primed to explode
- primed to fire
- disarm
to remove the firing mechanism or make safe
Grammar Patterns
prime + bomb/gun
be primed to explode/fire
Usage Note
In modern civilian language, this sense is most common in news reports about military operations or in crime fiction. The related noun is 'primer', meaning the small charge used to set off a larger explosive.
Word family
Synonym discussion
Sense: adjective/1
All four words indicate something of top importance, but they differ in nuance and context. 'Main' is the most neutral and widely used in everyday conversation ('the main entrance', 'the main point'). 'Primary' carries a slightly more formal or academic tone and often suggests first in sequence or priority ('the primary goal of the experiment'). 'Chief' has a sense of leadership or highest rank within a group ('the chief concern of the committee'). 'Principal' is similar to 'primary' but leans toward financial or institutional contexts ('the principal reason', 'the principal investor'). In most everyday situations, 'main' or 'prime' are natural choices; 'primary' and 'principal' suit more formal writing. For example: 'The main problem is traffic' sounds natural in casual talk, while 'The primary objective of the study was to test the new drug' fits a research report.
Common collocations
Nouns
- prime number
- prime minister
- prime rate
- prime time
Phrases
- prime of life
- prime of one's career
- prime cut of meat
- prime candidate
- prime location
Prepositions
- in one's prime
- past one's prime
- prime for (a situation)
- prime with (information/primer)
Etymology
Prime comes from Latin 'primus', meaning 'first'. It entered English through Old French 'prime' and originally referred to the first hour of the day in religious contexts. Over time it developed the broader senses of 'first in importance' (adjective), 'the first or best period' (noun), and 'to make something ready for first use' (verb). The mathematical sense of a number that cannot be factored — i.e., 'first' or 'basic' — appeared in the 16th century.