1. Plugging in something to a live circuit when what is being plugged in does not have a switch that must be activated for the object to work, such as most theatrical fixtures. An instrument plugged into a live circuit will be on instantly because the circuit is completed, this is hot-patching. A home desk lamp requires you to activate an inline switch (usually) and thus complete the circuit, this is not hot patching. This method is most commonly used to test a broken piece of equipment or lamp, it is not a recommended practice and can go from hazardous to deadly very quickly.
See also Patch, Types of (Lighting).
2. May also refer to an area of a touring dimmer rack to provide constant power to non-dimmable devices. Also known as "Hot Pockets."