A caption is a short piece of text that explains or describes a picture, photograph, or illustration. When you flip through a magazine or scroll through social media, those few words underneath or beside each image are captions. They might identify who's in a photo, explain what's happening, tell you where it was taken, or add a funny comment.

Captions serve different purposes depending on where they appear. In a textbook, a caption might read “The Wright Brothers' first flight at Kitty Hawk, 1903” to help you understand a historical photograph. In a family photo album, someone might write “Emma's eighth birthday party” so people remember the occasion years later. On social media, captions often add personality or humor to images.

The word also refers to subtitles at the bottom of a video screen that show what people are saying. These captions help people who are deaf or hard of hearing follow along, and they're useful when you're watching something in a noisy room or need to keep the volume down.

Think of captions as the voice of an image. A picture might be worth a thousand words, but sometimes a well-chosen caption of just five or six words can tell you exactly what you need to know.