Streaming Glossary: Every Term and Feature Explained

Streaming services use technical jargon that can be confusing for subscribers trying to choose the right plan or understand what they are getting. This glossary explains every important term clearly so you can make informed decisions about your streaming setup.

Video Quality Terms

4K Ultra HD refers to a resolution of 3840 x 2160 pixels — four times the detail of standard 1080p HD. On televisions 50 inches and larger, the difference between 1080p and 4K is clearly visible, particularly in detailed scenes with fine textures. Most streaming services require their premium tier to access 4K content.

HDR (High Dynamic Range) improves the contrast between the brightest and darkest parts of the image. An HDR picture shows more detail in shadows and more vivid highlights than SDR (Standard Dynamic Range). Your TV must support HDR to benefit from HDR content.

Dolby Vision is a premium HDR format that uses dynamic metadata — it adjusts the picture scene by scene and even frame by frame, rather than applying a single setting to the entire film. Dolby Vision generally looks better than standard HDR10 because it optimizes for your specific display. Apple TV Plus, Netflix, Disney Plus, and Max all offer Dolby Vision content.

HDR10 and HDR10+ are the two other common HDR formats. HDR10 is the baseline standard supported by all HDR TVs. HDR10+ (supported by Amazon Prime Video and Samsung TVs) adds dynamic metadata similar to Dolby Vision but without the licensing fee.

Audio Terms

Dolby Atmos is a spatial audio format that adds height channels to surround sound, creating a three-dimensional sound field. In a home theater, Atmos uses upward-firing speakers or ceiling speakers to place sounds above the viewer. For streaming, Atmos creates a noticeably more immersive experience for action sequences, nature documentaries, and music performances.

5.1 Surround Sound is the standard surround format — five speakers plus a subwoofer. Most streaming content is available in 5.1, and most soundbars simulate 5.1 output.

Stereo is two-channel audio — left and right. This is what you get from TV speakers and basic earbuds. Streaming content defaults to stereo when no surround system is detected.

Streaming Service Terms

Simultaneous Streams refers to how many people in your household can watch different content at the same time. Netflix Premium allows four; most platforms offer one to four depending on the tier.

Offline Downloads allow you to save content to your device for viewing without an internet connection. Not all plans include this feature — ad-supported tiers often exclude it.

Ad-Supported Tier provides full or near-full access to a platform’s library at a reduced price, with commercial interruptions. The ad experience varies by platform — some insert ads only before content, others include mid-roll breaks.

Bitrate is the amount of data transmitted per second. Higher bitrate means better picture and audio quality but requires more bandwidth. Apple TV Plus generally streams at the highest bitrate; Netflix adjusts bitrate based on your connection speed.

Device Terms

Streaming Device is any hardware that connects to your TV and runs streaming apps — Roku, Amazon Fire TV Stick, Apple TV 4K, Chromecast, gaming consoles, and smart TV built-in apps.

Casting sends content from your phone or tablet to a TV-connected device like a Chromecast. AirPlay is Apple’s version, sending content from iPhones, iPads, and Macs to Apple TV or compatible smart TVs.

HDMI eARC (Enhanced Audio Return Channel) is the HDMI connection type that carries high-quality audio formats like Dolby Atmos from your TV to a soundbar or receiver. Without eARC, you may lose Atmos support when routing audio through your TV.

Common Confusion

4K is not the same as HDR. A TV can be 4K without HDR, or 1080p with HDR. The best experience comes from having both. Dolby Vision and Dolby Atmos are separate technologies. Vision is video; Atmos is audio. A show can have one without the other.

For platform-specific details on quality tiers, see Best Streaming Services for 4K and Dolby Atmos and the Best Streaming Services Compared guide.