Lineup: A channel's lineup describes its programming sequence. Channel lineups are looped infinitely and based off of the channel's start time.
Programming: A channel's programming refers the actual media in a channel lineup
Filler: Filler content refers to media that is used to "round out" a schedule. For instance, a 22-minute television episode may need 8 minutes of "filler" distributed within a 30-minute slot to replicate a true "TV" experience
Flex: Flex time refers to chunks of time in which one or more pieces of filler are placed within a channel lineup. Content used to fill periods of flex time are not chosen until stream time.
Padding: Padding generally refers to applying flex time in order to have content start at "nice" times, e.g. 12:00, 12:30, etc.
Slot: Tunarr includes programming tools called slot editors. Using slots allows for fine-grained control over channel lineups. A slot refers to a "grouping" of programming with either a set duration or start time.