Glossary
Vertical video, explained
Plain-English definitions of the terms behind short-form video — vertical formats, YouTube Shorts, Instagram Reels and TikTok, content creation, AI video and social sharing.
Short-form & vertical video
- 9:16
- The aspect ratio of vertical video: 9 units wide for every 16 tall, commonly 1080 × 1920 pixels. It is the standard for TikTok, Reels and Shorts.
- Aspect ratio
- The proportion of a video's width to its height, written as width:height. 16:9 is landscape (TV, YouTube), 1:1 is square, and 9:16 is vertical.
- Faceless channel
- A social or video channel where the creator never appears on camera — content is built from voiceover, stock or AI visuals, text and music. Popular for explainers, stories, facts and kids' content.
- For You Page (FYP)
- TikTok's main feed of recommended videos, personalised for each viewer. Videos can reach large audiences here even from accounts with few followers.
- Instagram Reels
- Instagram's short-form vertical video format, shown in the Reels tab, the main feed and Explore.
- Loop
- When a short video restarts automatically after it ends. Videos whose ending flows back into the beginning often earn extra watch time from repeat views.
- Safe zone
- The central area of a vertical video that isn't covered by the platform's own interface — captions, usernames, buttons. Important text and faces should stay inside it.
- Short-form video
- Video built to be watched in under a few minutes — usually 15 to 90 seconds — on a phone, inside an endless scrolling feed. TikTok, Instagram Reels and YouTube Shorts are the main short-form platforms.
- TikTok
- A social platform built entirely around short-form vertical video, with a personalised For You feed driven by its recommendation algorithm.
- Vertical video
- Video shot or edited taller than it is wide, typically at a 9:16 aspect ratio, so it fills a phone screen held upright. It is the native format of short-form feeds.
- YouTube Shorts
- YouTube's short-form vertical video format, shown in a swipeable feed separate from regular YouTube videos.
Content creation
- Call to action (CTA)
- A prompt asking the viewer to do something next — follow, comment, visit a link in bio, or watch part two.
- Content calendar
- A schedule of what will be published and when. It helps creators post consistently instead of reactively.
- Hook
- The first one to three seconds of a short video, designed to stop the viewer scrolling — a bold claim, a question, a surprising image or the payoff shown first.
- Niche
- The specific topic or audience a creator focuses on, such as science facts, kids' stories or personal finance. A clear niche helps platforms show videos to the right viewers.
- Posting cadence
- How often an account publishes, such as daily or three times a week. Consistent cadence helps audiences and algorithms know what to expect.
- Repurposing
- Turning one piece of content into others — for example cutting a long video into several shorts, or posting the same short to several platforms.
- Retention
- How much of a video viewers watch before swiping away, usually shown as a percentage or a retention curve. High retention is one of the strongest signals recommendation algorithms use.
- Script
- The written plan for what a video says and shows, scene by scene. Short-form scripts lead with a hook and keep each scene to a line or two.
- Series
- A run of related videos sharing a format, character or theme, often numbered. Series give viewers a reason to follow for the next episode.
- Storyboard
- A scene-by-scene plan of a video's visuals, often sketched or described in words, used to plan shots before producing them.
- Trending audio
- A sound or song many creators are using at the same time. Using it can help a video get discovered while the trend lasts.
- User-generated content (UGC)
- Content made by customers or creators rather than by a brand itself, often used in ads because it feels authentic.
- Watch time
- The total time viewers spend watching a video. On short-form platforms, average watch time relative to the video's length matters more than the raw total.
AI video
- AI video generator
- Software that creates video from a text description using AI models — writing the script, generating visuals, synthesising a voiceover and assembling the edit. Slice is an AI video generator for vertical shorts.
- Consistent character
- A person or mascot whose appearance stays the same across every scene and video an AI generates, usually by pinning generation to a reference image.
- Image-to-video
- AI generation that animates a still image into a short clip, keeping the image's look and composition. Slice animates its own stills this way so motion scenes match the rest of the video.
- Motion model
- An AI model that generates movement — animating a still image or creating a video clip — as opposed to an image model, which creates single frames.
- Prompt
- The written instruction given to an AI model describing what to create. Clear, specific prompts produce better results than long lists of technical requirements.
- Style preset
- A saved visual style — such as photorealistic, cinematic, anime or Pixar-style 3D — applied consistently to every scene of a video.
- Text-to-speech (TTS)
- AI that turns written text into natural-sounding spoken audio, used for voiceovers.
- Text-to-video
- AI generation that produces a video clip directly from a written description (a prompt).
- Voice cloning
- Creating a synthetic copy of a specific person's voice from a short recording, so text can be spoken in that voice. It should only be done with the person's consent.
Video production
- B-roll
- Supporting footage that illustrates what is being said, cut in over the main narration.
- Burned-in captions
- Captions rendered permanently into the video image, so they show on every platform and player — also called open captions.
- Captions
- On-screen text showing what is being said. Most short-form video is watched with the sound off at least some of the time, so captions are close to essential.
- Frame rate
- How many still frames make up each second of video, measured in frames per second (fps). 24, 30 and 60 fps are common.
- Jump cut
- An abrupt cut that skips time within the same shot, used to remove pauses and keep short videos fast-paced.
- Ken Burns effect
- A slow pan and zoom across a still image that gives it a sense of motion. It is the classic way to bring photographs to life in video.
- Render
- The process of combining scenes, audio, captions and effects into a final playable video file. Exporting usually means rendering at full quality.
- Resolution
- The number of pixels in a video frame. For vertical video, 1080 × 1920 is the common standard.
- Royalty-free music
- Music licensed for use in videos without paying a fee per play or per view. AI-generated music can also be used where its licence allows.
- Timeline editor
- An editing interface that lays a video's scenes, audio and text along a timeline so they can be trimmed, reordered and restyled.
- Voiceover
- Narration recorded or generated separately from the visuals and laid over them. Most faceless videos are driven by voiceover.
- Word-synced captions
- Captions timed to the exact moment each word is spoken, often highlighting the current word (karaoke-style).
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