Glossary
What is a hook?
By the KeyMo team · Updated
A hook is the opening line or image of a clip, meant to make a viewer stay past the first seconds. In video it is the first thing said or shown. In writing it is the first sentence, in music a catchy phrase, and in React something else again. A good video hook makes sense with no context.
Hook definition in video
When people clip a long interview, the hook is the first sentence a stranger hears. Nobody scrolling has seen the first forty minutes, so the opening has to carry its own meaning. A hook works when it states a claim, asks a question the viewer wants answered, or shows something unexpected.
It is not a trick. The test is whether the hook promises something the rest of the clip delivers. A hook that over-promises gets the first second and loses the viewer by the tenth.
Three openings and why they work or fail
These lines were written for this page to show the pattern. They are not quotes from real shows.
| Opening line | Verdict | Why |
|---|---|---|
| "Thanks so much for having me, I'm really excited to be here." | Fails | A greeting. It says nothing about what the clip is about. |
| "Most people quit their first business for the wrong reason." | Works | A claim that stands alone and invites the question: which reason? |
| "Right, and that's the second thing I wanted to get to." | Fails | Depends on context. Second after what? The viewer has no way in. |
Decision rule: read the first sentence of a clip aloud with no context. If a stranger could not say what it is about, cut forward to the next sentence that could be understood alone.
What the platforms say about the opening seconds
- Instagram for Creators advises making the first 3 seconds engaging so people do not move on. It gives no retention target.
- YouTube defines Engaged views as views where the viewer stayed past the initial seconds, and its Stayed to watch measure uses the same wording. The pages read never say how many seconds that is.
- TikTok's ad guidance recommends the hook within the first 6 seconds and the content proposition within the first 3. That is advice for ads, not a rule for ordinary posts.
In short, no platform page read here gives one magic duration for an organic video. Treat "3 seconds" as advice, not a measured cutoff. The first 3 seconds guide goes into the cut itself.
Hook in other fields
- Writing and literature: the opening sentence or scene that makes a reader keep going.
- Music: a short, catchy phrase that repeats and sticks in the head, often in the chorus.
- React: a function that lets a component use features such as state. No relation to video, and it shares only the name.
- For kids: the first thing that makes you want to keep watching or reading.
Hook vs nearby terms
A cold open is a scene shown before the title, and a hook can be the first line of one. A visual hook is the same idea done with an image instead of a line, and a pattern interrupt is a change that breaks the viewer's autopilot. A hook is the opening, pacing is how the rest moves.
Where KeyMo touches it
KeyMo gives each clip a score out of 10 and a one-line reason, trims silence, and lets you choose a length from 15 to 90 seconds. It does not claim to write hooks for you. Use the reason line as a prompt to check whether the opening says what makes the moment good.
Sources: Instagram for Creators: FAQ (first 3 seconds) (checked 11 October 2026); YouTube Help: Shorts analytics (Engaged views and Stayed to watch) (checked 11 October 2026); TikTok Ads Help: Creative best practices (checked 11 October 2026).