once every three weeks

USAGE SUMMARY

The part of the sentence 'once every three weeks' is correct and usable in written English.
It is used to describe something that happens at a regular interval, for example, "I go to the gym once every three weeks".

✓ Grammatically correct

News & Media

Science

Academia

Human-verified examples from authoritative sources

Exact Expressions

60 human-written examples

In a randomized, controlled, parallel group trial design with two groups, one receiving family-assisted social cognitive training once a week (F-SCIT) and the other, social stimulation once every three weeks (SS), both for 14-weeks period, patients were assessed at baseline, before randomization and 16 weeks after randomization.

Psychiatry Research

Most clerks are audited once every three weeks, he said.

The New York Times

Women can insert it themselves, like a diaphragm, once every three weeks.

The New York Times - Health

Electives will generally be scheduled during the regular block format (three-hour classes Thursday - Saturday, once every three weeks).

University of California, Berkeley

"It's a bit more demanding, but taking a long weekend once every three weeks fits my schedule better".

The New York Times

"We saw each other once a week for a while, then about once every three weeks," he told me.

The New Yorker

Mom served them to us for dinner at the table in the Soundview kitchen about once every three weeks.

The New York Times - Magazine

Currently studying stage management at Marymount College in New York, Halperin attends theatre about once every three weeks.

The Guardian

The co-worker said Ms. Miranda traveled roughly once every three weeks to San Francisco, always first class.

The New York Times

The parents used to have a regular Sunday night meeting, which has now turned into once every three weeks.

The New York Times

At least once every three weeks, the Obama campaign calls supporters, making sure they are still committed.

The New York Times

Expert writing Tips

Best practice

Use "once every three weeks" to clearly indicate the frequency of an event or action, especially when comparing it to other time intervals.

Common error

Avoid mixing "once every three weeks" with other frequencies in the same context without clear distinction. For example, instead of saying 'Tasks are reviewed weekly, then once every three weeks,' specify 'Tasks are reviewed weekly, then less frequently, once every three weeks.'

Linguistic Context

The phrase "once every three weeks" functions as an adverbial phrase, modifying a verb to specify how frequently an action occurs. Ludwig AI confirms its correct usage.

Expression frequency: Very common

Frequent in

News & Media

60%

Science

25%

Academia

10%

Less common in

Wiki

3%

Formal & Business

2%

Reference

0%

Ludwig's WRAP-UP

The phrase "once every three weeks" is a common and grammatically correct adverbial phrase used to indicate the frequency of an event or action. As Ludwig AI confirms, it's widely used across various contexts, including news, science, and academia. Its purpose is to clearly specify the interval between occurrences. While alternatives like "every three weeks" or "triweekly" exist, "once every three weeks" provides a specific emphasis on a single occurrence within that period. Therefore, be accurate with your time frames and use ""once every three weeks"" in your writing when emphasis is needed.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

every three weeks

Slightly shorter, omits the "once" for brevity.

once in three weeks

Rearranges the word order slightly.

triweekly

Uses a single word to convey the same frequency.

every third week

Rephrases using ordinal numbers.

approximately every three weeks

Adds a qualifier for an estimated frequency.

at three-week intervals

Emphasizes the consistent spacing between occurrences.

every 21 days

Provides a precise numerical equivalent.

on a three-weekly basis

More formal, using a business-oriented term.

one time per three weeks

More verbose, emphasizing the single occurrence.

every few weeks

Less precise, indicating an approximate timeframe.

FAQs

How can I use "once every three weeks" in a sentence?

You can use "once every three weeks" to describe the frequency of events. For example, "The team meets "once every three weeks" to discuss progress."

What are some alternatives to saying "once every three weeks"?

Alternatives include "every three weeks", "triweekly", or "every third week". The best choice depends on the desired level of formality and precision.

Is it correct to say "one time every three weeks" instead of "once every three weeks"?

While "one time every three weeks" is understandable, ""once every three weeks"" is more concise and commonly used.

What is the difference between "every three weeks" and "once every three weeks"?

"Every three weeks" implies a recurring event, while ""once every three weeks"" emphasizes a single occurrence within that timeframe. The difference is subtle, but the "once" can add emphasis.