What is a message thread?

A series of messages

In emails and online, people often refer to a string of messages that make up a conversation as a "thread." For example, a Redditor may post, "Tell me how you prepare your eggs," and other Redditors might reply with their methods, creating a thread.

Since the increased usage of email and the advent of social media in the 2000s, threads have become commonplace. As a result, you will see threads on social sites like Twitter, Facebook, Instagram, and Reddit, where conversations are the core aspect of their existence.

However, each app, service, site, etc., displays threads differently. For example, Twitter shows replies to a tweet differently than how Facebook organizes comments in a thread.

Besides social media, you will also see threads in online forums, messaging apps, and email services. Like with social media, these services display posts and email messages differently.

Different thread formats

Typically, you will see threads displayed in one of two formats:

  • Linear or flat - Each message in the thread appears chronologically.
  • Hierarchical or nested - Each message relates to the message it is replying to, which is helpful when displaying subthreads.

Many sites and services also allow you to filter messages in a thread by how popular they are, their recency, etc.


Did you see Drew's comment in the thread yesterday?
Yeah, I can't believe he said that
I'm pretty sure he didn't realize it would show up as a reply to everyone
A Twitter thread tease comparing Batman movies
A Twitter thread tease comparing Batman movies
An example of a Reddit thread
An example of a Reddit thread

Related Slang


Updated August 16, 2022

Thread definition by

This page explains what the slang term "Thread" means. The definition, example, and related terms listed above have been written and compiled by the team.

We are constantly updating our database with new slang terms, acronyms, and abbreviations. If you would like to suggest a term or an update to an existing one, please let us know!