A thread is Twitter’s feature for publishing a sequence of connected posts as one conversation. Users can compose several posts together so readers can follow an extended explanation, story or update in order.
Threads became especially useful because individual Twitter posts historically had strict character limits. Before the built-in composer supported threads, users often numbered separate posts manually or replied to their own messages. Twitter later added a dedicated thread-composition interface that made the format easier to create.
A thread is not the same as a reply chain started by different people. A thread generally presents posts written by the same author as a connected series, while a conversation can include replies from many accounts. X retained threaded posting after Twitter was renamed in 2023.