'Bi-Weekly' vs 'Semi-Weekly': What's the Difference?

By Carly Forsaith, updated on January 13, 2023

'Bi-weekly' vs 'semi-weekly' are two terms that are often confused. In this article, I'll clarify the meaning of each one and when to use them.

In summary, 'bi-weekly' means every two weeks, and 'semi-weekly' means twice a week.

Difference Between 'Bi-Weekly' vs 'Semi-Weekly'

The difference between these two words is in the prefix. You've got the adjective 'weekly,' and then you've got the prefixes' bi-' and 'semi-.'

Sometimes, you might also see them written without a hyphen, like this:


Both the hyphenated and non-hyphenated spellings are correct.

Both words can be adjectives, adverbs, or nouns, depending on the context and the other words in the sentence.

The key to understanding each word better is to grasp the meaning of these prefixes.

Definition of 'Bi-Weekly'

When something happens bi-weekly, it happens once every two weeks. The prefix 'bi-' comes from the Latin meaning "twice, double," hence bi-weekly means double-week, so there are two weeks between each release.

Here are some other words that have the prefix 'bi-':

  • Bisexual
  • Bilingual
  • Binary

Top Tip! The Brits use "fortnightly" to mean biweekly.

Definition of 'Semi-Weekly'

'Semiweekly' means twice a week. The prefix 'semi' comes from the Latin meaning "half." That's why a 'semiweekly' is released after each half of the week, making it twice a week.

Here are some other words that have the prefix 'semi-':

  • Semiautomatic
  • Semicircle
  • Semiprofessional

Pronunciation: How to Pronounce 'Bi-Weekly' and 'Semi-Weekly'

To understand how to pronounce 'bi-weekly' vs 'semi-weekly,' we'll look at the pronunciation of three words: 'bi,' 'semi,' and 'weekly.'

Here's the International Phonetics Association's spelling of each word:

Bi → /baɪ/
Semi → /ˈsemi/
Weekly → /ˈwikli/

And here's our interpretation of how these words sound:

Bi → bahy
Semi → sem-ee
Weekly → week-lee

When to Use 'Bi-Weekly' and 'Semi-Weekly'

Now that you're clear on the meaning of each term let's dive in a little deeper with some examples of each word used in a sentence. This will help you understand even better when you can use these terms.

Examples of 'Bi-Weekly'

Let's start with 'bi-weekly.' In each example, I'll specify whether the word functions as an adjective, adverb, or noun.

I know what we could do for our English project: let's set up a bi-weekly paper! (adjective)

She's been trying to release blogs biweekly, but they're taking longer to write than she'd anticipated. (adverb)

They're proud to announce a bi-weekly starting next month. (noun)

This subscription entitles you to receive a box biweekly. (adverb)

Subscribe to our bi-weekly newsletter to keep up to date with our latest news and promotions. (adjective).

Examples of 'Semi-Weekly'

Now let's look at examples of 'semi-weekly.' Here also, I'll specify whether the word functions as an adjective, adverb, or noun.

Semiweeklies are a popular format for some publications. (plural noun)

We're going to start releasing a semi-weekly edition of our column. (adjective)

I was hoping send a newsletter semiweekly, but I don't have the time. (adverb)

They've started publishing a semi-weekly. (noun)

It's crucial that we stay consistent with semiweekly meetings. (adjective)

The Bottom Line for 'Bi-Weekly' vs 'Semi-Weekly'

Yes, these two words often need clarification, and it's easy to see why. If you're in doubt, trying to remember other words with those prefixes to remind yourself of the meaning can be helpful.

You know that 'bilingual' is to speak two languages, so the frequency is double.

You know that semicircle' means a half circle, so the frequency is after each half of the week.

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Written By:
Carly Forsaith
Carly Forsaith is one of the lead freelance writers for WritingTips.org. Carly is a copywriter who has been writing about the English language for over 3 years. Before that, she was a teacher in Thailand, helping people learn English as a second language. She is a total grammar nerd and spends her time spotting language errors on signs and on the internet.

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