A bump is any change of a lighting state that happens in zero time, i.e. bump to full, bump to black, bump to frame#1, bump to full body. Those who've ever run a multi-scene preset console are familiar with the seemingly (but not) oxymoronic term: "bump crossfade". For more, see this thread.
Technically a "blackout" is a bump to black, not a fade to black, although often directors and non-lighting people will use the term "blackout" when they mean "fade to black".
Technically a "blackout" is a bump to black, not a fade to black, although often directors and non-lighting people will use the term "blackout" when they mean "fade to black".