Half Day or Half-Day?

In the vast landscape of the English language, compound words play a significant role in conveying meaning efficiently. One such compound that often sparks confusion is “half day” or “half-day.” Both forms are frequently used, but which one is correct? Does it matter which one you choose? Let’s delve into the nuances of compound words and shed light on their usage.

Understanding Compound Words

Before delving into the specifics of “half day” versus “half-day,” it’s crucial to understand what compound words are. Compound words are formed by combining two or more words to create a new word with its own distinct meaning.

These combinations can be nouns, adjectives, verbs, or adverbs, and they can be written in various forms, including closed (e.g., “lunchbox”), open (e.g., “post office”), or hyphenated (e.g., “well-known”).

Half Day

“Half day” is a compound word commonly used to refer to a period of time equal to half of a full working day. In this context, “half” serves as an adjective describing the noun “day.”

For example:

  •  “Employees are allowed to take a half day off on Fridays during the summer months.”
  • “The conference will conclude at noon, making it a half day for attendees.”

In these instances, “half day” is written as two separate words without a hyphen. This form is widely accepted and commonly used in both formal and informal contexts.


On the other hand, “half-day” is also a compound word that refers to the same concept—a period of time equal to half of a full day—but with a slight variation in spelling. In this case, the hyphen between “half” and “day” serves to connect the two words, indicating that they function together as a single unit.

For example:

  • “The school announced an early dismissal for a half-day due to inclement weather.”
  • She decided to schedule her dentist appointment for a half-day to minimize disruption to her work schedule.”

In these scenarios, “half-day” is written with a hyphen, indicating that “half” and “day” are linked together to form a compound adjective describing a period of time.

Use of Half-Day or Half Day According to Writing Styles

When it comes to the English language, precision and consistency are paramount, especially when dealing with compound words. The decision between “half day” and “half-day” is not merely a matter of personal whim; it often aligns with the guidelines set forth by various style guides. Let’s explore how these influential guides shape our language choices and impact the use of compound words.

The Associated Press (AP)

The AP Stylebook, a go-to reference for journalists, tends to prioritize simplicity. It generally favors the open or closed form of compound words.

For “half day” or “half-day,” the AP Stylebook recommends the open form: “half day.”


  1. The team decided to take a half day off after a successful project completion.
  2. She enjoyed a leisurely half day exploring the local markets.

The Chicago Manual of Style (CMS)

CMS, a comprehensive guide used in publishing and academia, emphasizes the use of hyphens for clarity in compound words.

For “half day” or “half-day,” CMS advocates for the hyphenated form: “half-day.”


  1. The conference organizers scheduled a half-day workshop on effective editing techniques.
  2. The professor allowed the students to leave early, declaring it a productive half-day of class.

American Psychological Association (APA)

Commonly used in the social sciences, APA style prioritizes clarity and simplicity in writing.

For “half day” or “half-day,” APA style typically supports the closed or open form, making “half day” a preferred choice.


  1. The research team concluded their experiment, marking it a successful half day of data collection.
  2. Participants in the study were compensated for their time with a half day of extra leave.


The debate between “half day” and “half-day” is emblematic of the intricacies inherent in the English language. The guidance provided by style guides serves as a compass, helping writers chart their course through the complexities of compound word usage.

Whether you choose the open, closed, or hyphenated form, understanding the preferences of major style guides empowers you to navigate the seas of compound words with confidence. So, whether you’re drafting a journalistic piece or an academic essay, let the guiding principles of style help you navigate the often turbulent waters of language conventions.

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