8 terms, checked against YouTube's help pages

YouTube thumbnail glossary

The words YouTube Studio uses around a thumbnail, in plain English: what each one counts, where to find it, and what it changes about the image you make.

A

Formats & Specs16:9 Aspect Ratio16:9 is a frame 16 units wide for every 9 tall, about 1.78 to 1. It is the shape of a YouTube video and of its thumbnail.Read the definition Formats & Specs9:16 Aspect Ratio9:16 is a vertical frame 9 units wide for every 16 tall, about 0.56 to 1. It is the shape of YouTube Shorts and of their thumbnails.Read the definition

B

YouTube MetricsBrowse FeaturesBrowse features is the YouTube Analytics traffic source for views from the home page, the subscriptions feed, Watch Later and other browsing surfaces.Read the definition

I

YouTube MetricsImpressionsAn impression is one time YouTube showed your thumbnail to a viewer: more than one second on screen, with at least half of it visible.Read the definition YouTube MetricsImpressions Click-Through RateImpressions click-through rate (CTR) is the share of registered thumbnail impressions on YouTube that turned into a view.Read the definition

S

YouTube MetricsSuggested VideosSuggested videos is the YouTube traffic source for views from the suggestions shown next to or after another video, and from links in descriptions.Read the definition

T

Thumbnail DesignThumbnail Safe ZoneA thumbnail's safe zone is everything outside the bottom-right corner, where YouTube draws the duration badge on every video thumbnail.Read the definition

Y

YouTube StudioYouTube A/B TestingYouTube A/B testing shows up to three thumbnails or titles to different viewers and keeps the one that earns the most watch time.Read the definition

The practical side of each term lives in the guides and the free tools.