Glossary
Short-form video glossary
Plain-English definitions of the Instagram Reels, TikTok, and Shorts terms that actually decide reach. The signals rank in this order: skip rate first, then shares, likes, saves, reposts, comments.
- Hook
- The first 1 to 3 seconds of a Reel: the opening visual, on-screen text, and audio that decide whether a viewer keeps watching or swipes away. A strong hook lowers skip rate, the single biggest driver of reach.
- Hook Rate
- The share of viewers who stay past the first few seconds instead of scrolling. It is often estimated as views relative to impressions. A low hook rate means people see the Reel but swipe before it really starts.
- Skip Rate
- The percentage of viewers who swipe past a Reel in the first few seconds. It is the first signal the algorithm reads and the most important one: a high skip rate caps reach before anything else can count.
- Retention Rate
- How well a Reel holds viewers across its length, shown as a curve from 0 to 100 percent. The shape reveals where attention breaks: a cliff in the first 3 seconds points to a weak hook; a steady decline usually means pacing or length.
- Completion Rate
- The percentage of viewers who watch a Reel all the way to the end. It matters most for short Reels (under about 15 seconds), where finishing is easy and signals satisfying content.
- Watch Time
- The total (or average) time viewers spend watching a Reel. It rewards depth of attention and matters most for longer Reels, where holding someone for 40 of 90 seconds is a strong signal even if few finish.
- Reach
- The number of unique accounts that saw a Reel at least once. Reach grows in batches: the algorithm shows the Reel to a small test audience first, then expands distribution if early retention and engagement are strong.
- Impressions vs Views
- Impressions count how many times a Reel appeared on screen; views (now Instagram's unified metric) count plays. The gap between them reflects how many people scrolled past versus actually watched.
- Drop-off Point
- The exact moment in a Reel where viewers leave in large numbers, visible as a dip in the retention curve. Finding the drop-off second and the on-screen cause is the key to fixing a reel that underperforms.
- Engagement Rate
- The share of viewers who interact with a Reel (likes, comments, shares, saves) relative to reach or views. For reach, the signals that matter most run in this order: skip rate first, then shares, likes, saves, reposts, comments.
- Saves
- When a viewer bookmarks a Reel to return to later. Saves signal high-value, reference-worthy content and contribute to reach, though they rank below shares and skip rate.
- Replays / Loops
- When a viewer watches a Reel more than once. On short Reels, loops can push watch time above 100 percent of the video length, which the algorithm reads as very high value.
- Pattern Interrupt
- A sudden change in visuals, audio, or pacing that re-captures attention and resets a viewer's urge to scroll. Frequent pattern interrupts (a cut, zoom, caption, or b-roll every 1 to 3 seconds) help hold retention.
- Call to Action (CTA)
- The prompt at or near the end of a Reel telling viewers what to do next (follow, save, comment, tap the link). A clear CTA converts attention into action, and placed after the payoff it does not hurt retention.
- Reels Algorithm
- The ranking system that decides how far a Reel spreads. It tests each Reel on a small audience, watches early behavior (especially skip rate and retention), classifies the content by topic, then expands or caps reach accordingly.
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