In the television industry, a lower third is a graphic overlay placed in the title-safe lower area of the screen, though not necessarily the entire lower third of it, as the name suggests.
In its simplest form, a lower third can just be text overlying the video. Frequently this text is white with a drop shadow to make the words easier to read. A lower third can also contain graphical elements such as boxes, images or shading. Some lower thirds have animated backgrounds and text.
Lower thirds can be created using basic home-video editing software or professional-level equipment. This equipment makes use of video's alpha channel to determine what parts of the graphic or text should be transparent, allowing the video in the background to show through.
Lower thirds are also often known as "CG" (from character generator) or captions, and sometimes chyrons in North America, due to the popularity of Chyron Corporation's Chiron I character generator, an early digital solution developed in the 1970s for rendering lower thirds. Other common terms include superbars (or simply supers) (US), name straps and astons (after Aston Broadcast Systems) (UK).
Video with lower thirds is known as a "program as broadcast" or as "dirty"; video without lower thirds is known as a "clean feed" or as "textless". For international distribution, programs often include "textless elements" on the master tape – these are all the shots to which lower thirds (and other digital on-screen graphics) have been applied, placed end-to-end so a clean master can be created if necessary.
Lower thirds are usually arranged in tiers, or lines:
Lower thirds increasingly include elements such as news tickers, time and date, weather information, stock quotes, or sports scores.