A slug is like a teaser that summarizes a show. Not typically used in anything other than news TV and radio, but occasionally seen in entertainment. Example:
- "Flooding has claimed three lives in anywhereville, please tune in for details".
For syndicated shows, the slug may be a short episode synopsis that the local station gets in the syndication deal. The local station will tack on a card at the end showing the time the show will run. Example:
Related to Tonight, Someone Dies.
Websites, news and blogs in particular, use a slug for a mnemonic URL for content. For example this exact TVTropes page's slug is TheSlug.