7 Best Words for a Period of Four Months (1/3 of a Year)

There aren’t many words available to use when referring to a period of four months. Other terms relating to years like “monthly” and “bi-monthly” refer to one and two months, respectively. This article will look at what you might be able to use for four-month periods (1/3 of a year).

Best Words for a Period of Four Months

The preferred words are “four months,” “quadrimester,” and “tri-annually.” “Four months” is the most common one to use, and you’ll find that a lot of native speakers stick to this without overcomplicating anything. “Quadrimester” and “tri-annually” are a bit more specific in their contexts.

Four Months

“Four months” is the simplest way to refer to a period of four months. Most native speakers will use this phrase without overcomplicating it. There is no reason to include a word that nobody has heard of, which means you’ll have to spend extra time explaining it.

“Four months” is the easiest term that allows you to show exactly how much time has passed. Sometimes, the simplest options are the best ones. There is really no need to overcomplicate things.

For the most part, people would look at some of the other words on this list and wonder why you’re trying to make “four months” more complicated than it needs to be.

Also, four-month periods aren’t particularly common in English. Most of the time, you’ll refer to a period of either one, two, or three months. Anything after that can be split into relevant sections.

For example, you might say “quarterly,” which refers to a period of three months. It’s usually the largest number of months you can refer to with a single-word option.

  • It’s been four months since something like that happened last. We can’t let it repeat this time. We’ve got to fix it.
  • I didn’t realize it had been a full four months! I thought we still had plenty of time to work out a way to get through all of this.
  • You wanted to see me four months ago, but you still haven’t made the time to talk me through what’s going on. How rude!


“Quadrimester” is a good choice that relates to a period of four months. It uses the “quad-” prefix, which means “four.” People don’t use this one often because it isn’t an official word. However, its meaning is made quite clear through the context.

If you want to use “quadrimester,” native speakers will know what you’re talking about. It’s similar to the grammatically correct word “trimester,” which is why “quadrimester” is a decent choice if you want to extend the period to four months rather than the expected three.

Some people would argue that “quadrimester” should not be used. Since it’s not an official word, it makes more sense to avoid using it and stick to something simpler like “four months.”

  • I’ve been here for a full quadrimester, and I really didn’t think I was going to be here today. Man, I need to get my life together and move on.
  • A quadrimester is a surprisingly long time to be stuck doing something like this. I didn’t think we were going to have to waste our time here.
  • I thought you wanted this project to take the full length of the quadrimester. Clearly, you weren’t as invested in it as I was.


“Tri-annually” is a good one that shows that something happens three times a year. Generally, it happens at the same intervals each time, meaning that it will occur once every four months of a calendar year.

There are no specific rules that say something has to happen every four months. Technically speaking, if you say “tri-annually,” you could mean that it happens once every month for the first three months, but then it doesn’t happen again until the next year.

Nevertheless, “tri-annually” is still a great choice that usually shows a more uniform four-month period.

  • I know it’s supposed to happen tri-annually, but is there any way that we can speed the proceedings up just a little bit this time around?
  • I thought you were going to do this tri-annually. It definitely hasn’t been a third of the year yet, and you’re still going to do it anyway.
  • It happens tri-annually if that gives you anything to go on. It’s worth remembering that before you get stuck into anything new.

A Third Of A Year

“A third of a year” is obviously going to be a strong contender for a way to say “four months.” You can split twelve months (a full year) into three sections, allowing you to refer to four months at a time.

A lot of native speakers like this one, and it’s fairly common to use. The only reason it wasn’t included higher is that some people can have a tough time with fractions. It might cause them to be a bit confused about how many months you’re referring to.

  • We’ve been at this for a third of a year, and we still don’t have anything profound to show for it. I can’t believe we wasted all that time.
  • I’m not sure a third of a year is enough time for all of this to be planned correctly. I really think we should spend a bit longer on it.
  • It’s been a third of a year, and I still haven’t seen her come back to see me. I guess it really wasn’t meant to be. Oh well.


“Trimester” is an interesting choice that works in very specific circumstances. To preface this, “trimester” actually refers to a third of specific events, like an academic year or a pregnancy. Generally, this is closer to three months than four.

However, “trimester” can still be used to refer to one-third of a year. Since we’re looking at options for both four months and one-third of a year, “trimester” should be included.

While it doesn’t work for a full year, you can use it for an academic year without any issue. This technically still counts as a year (excluding the term breaks that students get). That’s why “trimester” can be a good choice for one-third of a year.

  • You’ll have to see me at the end of this trimester. I know that’s not ideal, but it’s the only way we can get this to work out well for you.
  • The academic trimester takes up a full third of the year. I don’t know if I can be bothered to sit around at college for that long.
  • Isn’t the trimester supposed to be one-third of the full term? I’m not sure you’ve been pregnant long enough for your first trimester yet.


“Quartile” can be used to refer to four months, but it’s not very common. A lot of people think it makes more sense when it’s used to refer to one-fourth of the year (which would actually be three months).

While there is a bit of confusion around this, it’s still possible for you to use “quartile” if you don’t have any better options. We highly recommend going with one of the other words on this list, but it’s worth knowing that “quartile” is an option, just in case.

  • The quartile is looking for good us. We’re finally getting some results that should set us up for a bit more success in the future.
  • I thought you were looking into the quartile this time around. I didn’t get a chance to look into it myself, which is very annoying.
  • Forgive me, but the quartile is going to have to wait. We need to make sure that everything is set up before moving forward.


“Tertile” is a bit closer to the meaning of four months than “quartile.” “Tertile” refers to one-third of the year, which equals four months. It’s not a very popular word in English, so you won’t hear it used, but it is still correct to refer to four months.

When it comes to words in English, it’s best to base your choices on those that are commonly used. Since most native speakers don’t use “tertile,” you’re better off avoiding it in most cases.

In fact, most people don’t even know what “tertile” means. You will save yourself a lot of time by using one of the less complicated words higher up in this article if you’re trying to show a four-month period.

The issue with words that aren’t well-known comes from the explanation that you have to give to them. Since nobody knows what “tertile” means, you’ll have to explain it. The time you take to explain it could have been saved by avoiding using it.

  • It’s been a tertile since we last saw each other. I’ve been keeping track, and I can’t believe how long we’ve let it go on.
  • I thought it was supposed to last for a tertile, but it appears you’ve already given up on the idea. We can’t just move on from this.
  • A tertile is a period of four months. That’s how long you’ve left me in the dark. I don’t know what I’m supposed to do now.