---
title: "What is a Subject line?"
canonical: https://www.beehiiv.com/newsletter-glossary/subject-line
description: "The text displayed at the top or beginning of an email, providing a concise summary and preview of the email's content. This line is visible in the recipient's inbox, influencing their decision to open or ignore the email."
source: live-converter
generated: 2026-08-13T05:04:51.328Z
---

# What is a Subject line?

-   [Newsletter Glossary](/newsletter-glossary)
-   Subject line

# Subject line

The text displayed at the top or beginning of an email, providing a concise summary and preview of the email's content. This line is visible in the recipient's inbox, influencing their decision to open or ignore the email.

In your beehiiv account, you can [A/B test](https://support.beehiiv.com/hc/en-us/articles/14493015046295-Subject-line-A-B-testing) your newsletter subject lines to determine the most effective variation.

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