1. Lighting. 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". 2. Rigging. A brief (0.5 - 1 second) pulse on a chain hoist control, resulting in very slight movement. "Up a bump"; "down a bump." Usually used with each hoist individually when leveling or setting a truss at a specific trim height. 3. See also the terms bump-in, bump-out as synonyms for load-in, load-out.