Understanding Emails: What Does “Re:” Mean in Email Subject Lines?

Melanie Balke
March 12, 2024

It may seem silly for an email marketing expert to be concerned about common abbreviations, but every little bit helps. Consumers have become accustomed to cluttered inboxes. Now, an original subject line isn’t enough to stand out. You need something more. You need to understand the culture behind modern emails.

So, to begin my series about understanding modern emails, I want to discuss one of the most common subject line additions.

“RE:” (sometimes written as “Re”) may seem outdated, but this formality has a purpose. While it’s no longer a requirement in modern email client systems, its longstanding use cemented it in modern parlance. Much like the floppy disk signifying modern save options, this little abbreviation is an anachronistic extension of formal email conversations.

Understanding the Meaning of “Re:”

You may see people claiming that this abbreviation is short for “reply.” In a way, it’s not wrong. It’s a shorthand form of the word, but this explanation is an oversimplification.

Today, most users remember the function of “RE” by thinking of it as an abbreviation of “regarding.”

However, if you trace the roots of this subject line filler to the beginning, you’ll learn some Latin! Originally, this signifier was an abbreviation of “in re.” The latter word derives from “rēs,” often translated to “stuff.” Thus, the whole phrase is often understood as “regarding” or “speaking of the topic.”

It is just one of many seemingly outdated abbreviations, including:

  • EOM: Short for “end of message,” this indicates that the email subject line is all you need to know.
  • FWD: Shorthand for a forwarded message; this is not an abbreviation for a fancy Latin phrase! You may also see it written as “FW.”
  • WAS: What it says on the box. This signifies that the subject line has changed. This is often placed at the end of a subject line. For example, you might see an email subject line like, “Discussing partnership at steakhouse (WAS: Where to meet with potential partner?).”

Why Would You Use “Re:” in an Email Subject Line?

Knowing that brings up another question.

Why would you use this term?

Today, email clients automatically append content to emails. Responding to an email message is as simple as clicking a button and typing your reply. Depending on your settings and client, that response is appended to the beginning or end of the original message.

In some respects, using “Re:” is an increasingly superfluous formality. However, it remains a stalwart presence in modern office parlance.

Emails as Extensions of Threaded Communication

At its core, an email is a thread. It’s a series of nested comments with little more than the sender’s name and the prior content’s context.

Early email software had little information attached to those crucial office comminqués. At best, you’d get the subject line and a long series of stacked responses. The addition of standard prefixes — such as “Re:” and “FWD” — was a courtesy. They informed the recipient of the message’s meaning and purpose.

You could even say these practices began with old-fashioned memos. Instead of stapling together massive binders of inter-office communication, offices would use shorthand to avoid confusion. In many settings, “Re:” indicated a message tied to another. Thus, readers could look at the requisite content and form a quick response without flipping through massive 20-page documents.

Courtesy and Efficiency

Of course, few workplaces use typewriters today.

Sending a new message is as simple as a few clicks.

Nonetheless, including this abbreviation can boost your business performance. Even now, decades after the first email, “Re:” signifies that content may require additional reading.

It’s also handy shorthand for letters, where it sees frequent use. The meaning doesn’t change, but it’s far more efficient to write “Re:” than “in regards to the previous message,” is it not?

A Word of Caution

That said, I don’t recommend using the phrase outside of work-related or B2B settings.

Technology has advanced. Its usage is mostly limited to written responses or printed communication. While its meaning is well-known among older audiences and office workers, it’s not a common phrase in daily life.

Trying to use “Re:” in a general sales email subject line will likely result in widespread confusion. Consumers who understand the abbreviation will likely wonder if the content is legitimate. At the same time, those who don’t know its meaning will ignore an otherwise incomprehensible message.

Learn More About Emails

Overlapping leaves. “Learn More: Discover the Power of Emails.”

That’s not to say you should never incorporate such formalities into your email marketing. It may have limited use, but this standardized abbreviation can work wonders in the right place. However, you must exercise caution with such things.

That’s why I founded The Email Marketers.

My team of marketing pros understands the complexities of modern emails. We work with businesses to formulate content that minimizes confusion and amplifies responses.

Schedule a free strategy session to see how we can maximize the efficacy of your email programs!