Suresh has joined a _____ course.


1) two year's

2) two years

3) two year

the answer is two year. but two year's sounds to me more logical. can you explain the nuance? thanks in advance.


two year course is correct and is used as an adjective (known as a compound adjective) to describe the length of the course which in this case is two years long.

Other examples of compound adjectives are:

  • a three day weekend.
  • a four metre rope.
  • a six cylinder engine.
  • a three year vacation.

Compound adjectives can be hyphenated or separated with spaces.

  • 8
    Your answer would improve if you gave a reference on the compound adjectives hyphen/no hyphen issue.
    – Ian
    Dec 5 '17 at 6:44

As others have said, the idiomatic answer is that you form an adjective phrase "two-year" to describe something relating to a period of two years (the plural is always dropped in this sort of construction). The hyphen ought to be used, though many people will write it without one. See this table from the Chicago Manual of Style (which includes "fifty-year" on page 2).

However, sometimes you will see similar phrases with a possessive construction. Some that spring to mind are "two weeks' notice" or "eight hours' sleep". The difference from your example is that here the time is quantifying how much notice/sleep you get, and I don't think you will see this construction except where you would ask something like "How much XYZ do you have?" (You wouldn't say "How much course has Suresh joined?")

No-one has yet pointed this out, but your option (1) would be wrong even for this construction because your apostrophe is in the wrong place: for the possessive of a plural ending in "s" like "years", put the apostrophe after the "s".


I do not know what you mean by "the answer is." This gets into the weeds of descriptive versus prescriptive grammar.

The first thing to realize is that "two years course," "two year's course," and "two years' course" sound exactly alike. In terms of spoken English, you will hear that set of sounds frequently enough to consider it idiomatic. You will also hear "two year course," which is indistinguishable from "two-year course," so that sound combination is idiomatic as well.

From a prescriptivist orientation, it is preferable to write "two-year course." The noun phrase "two-year" is being used as an adjective to modify "course.", and adjectives in English do not form plurals or possessives.


two year (or "two-year") describes the duration of something, and sounds natural when used to modify "course" as if "two year" was an adjective. This means a course which lasts for two years; it's common enough to see modifiers like this used in an uninflected form (plain "year"), rather than an inflected form.

two year's refers to the end-point of something. Side note, this is more properly written as two years', since the "two" means that "years" needs to be plural. This one isn't normally used with a noun like "course"; instead, it would much more common to hear it with "time". e.g., "Suresh has joined a course which ends in two years' time".

The version with the apostrophe could in theory be used as a straightforward possessive, but I can't think of any idiomatic cases where we do that in English with time durations.

And lastly, two years refers to a duration on its own. "a course lasting two years", for instance.

  • 6
    "two year's" is not good English in any context I can think of. The apostrophe makes it genitive, so it means "belonging to the two year", which does not normally make any sense.
    – RedSonja
    Dec 5 '17 at 12:19
  • Thank you (and the ~5 people who agreed) for confirming my hunch that the apostrophe should go after the "s". I was pretty sure that before the "s" would be a technically-incorrect variant at best, but didn't want to be prescriptive without being sure.
    – Soron
    Dec 5 '17 at 19:08

You should know that the apostrophe in the first answer makes it into the genitive case. Then it would mean "belonging to the two year", which does not make sense. It is a common mistake these days, but it is still totally wrong.

It started with fruit sellers labelling their wares "apple's" and "pear's"; nobody knows why they suddenly started making this error. So it is called "greengrocers' apostrophe".

Edit: corrected

  • I'm glad you mentioned that the possessive/genitive is nonsensical here; that's important. I think a better response would also mention "two-year" as an adjective the way user242899's did. Considered together, you two have the complete answer.
    – Gossar
    Dec 5 '17 at 8:24
  • If it meant "belonging to the two years", then it would be two years' rather than two year's. So it's definitely, definitely not that one :-)
    – psmears
    Dec 5 '17 at 10:08
  • @psmears oh ja should have been more observant! Quite right.
    – RedSonja
    Dec 5 '17 at 12:14
  • @Gossar mine is not the answer but a note about why the first suggestion was wrong.
    – RedSonja
    Dec 5 '17 at 12:16

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