# Glossary

- **AI UGC**: AI UGC is UGC-style video where AI produces some or all of the script, creator, voice or edit instead of a human filming it.
- **Answer engine optimization (AEO)**: Answer engine optimization is the practice of structuring content so AI assistants and search answer boxes can find, understand and cite it.
- **App Store Optimization (ASO)**: ASO is the process of improving an app's visibility and conversion rate in the App Store and Google Play through keywords, creatives and ratings.
- **Aspect ratio**: Aspect ratio is the width-to-height proportion of a video. TikTok, Reels and Shorts use vertical 9:16, typically 1080 by 1920 pixels.
- **CAC (customer acquisition cost)**: CAC is the total cost of acquiring one paying customer, calculated as acquisition spend divided by new paying customers.
- **Call to action (CTA)**: A call to action is the single instruction at the end of a video or post telling the viewer what to do next, such as "link in bio" or "search it on the App Store".
- **Completion rate**: Completion rate is the percentage of views in which the video was watched to the end.
- **Content calendar**: A content calendar is a schedule showing what will be posted, on which platform, when, and in what status.
- **Content pillar**: A content pillar is a recurring theme your account posts about, such as tips, demos or customer stories, that anchors your content calendar.
- **CPI (cost per install)**: CPI, or cost per install, is the advertising spend divided by the number of app installs it generated.
- **Engagement rate**: Engagement rate is the share of people who interacted with a post (likes, comments, shares, saves) relative to followers or views.
- **Hold rate**: Hold rate measures how well a video keeps viewers after the hook, commonly the share of viewers who reach a later point such as the 15-second mark or 50% of the video.
- **Hook**: A hook is the first one to two seconds of a short video: the line or visual that stops the scroll and earns the next few seconds of attention.
- **Hook rate**: Hook rate is the percentage of people who keep watching past the first few seconds of a video, usually measured as three-second views divided by impressions.
- **LTV (lifetime value)**: LTV is the total revenue, or gross profit, a customer is expected to generate over their entire relationship with your product.
- **Payback period**: Payback period is how long it takes for a customer's gross profit to repay what it cost to acquire them.
- **Posting cadence**: Posting cadence is how often you publish on a platform, for example three videos per week.
- **Retention rate**: Retention rate is the percentage of users who are still active after a given period, such as day 1, day 7 or day 30 after install.
- **ROAS (return on ad spend)**: ROAS is revenue attributed to ads divided by the ad spend that produced it. A ROAS of 2.0 means two dollars of revenue per dollar spent.
- **Safe zone**: A safe zone is the area of a vertical video where text and key visuals will not be covered by platform interface elements like captions, buttons and profile names.
- **Screen recording ad**: A screen recording ad is a video ad built around a real recording of an app or website in use, usually narrated by a creator voice-over.
- **Spark Ads**: Spark Ads are a TikTok ad format that promotes an existing organic post, keeping its engagement and creator handle.
- **UGC ad**: A UGC (user-generated content) ad is an ad made in the style of organic creator content: a real-looking person on a phone camera showing a product in use.
- **UTM parameters**: UTM parameters are tags added to a URL (source, medium, campaign, term, content) that tell analytics tools where a visit came from.