What is the definition or description of: nerve block?

Nerve block: Just means injecting a nerve with a local anesthetic, like lidocaine, to temporarily cause the nerve to stop working. It's usually done in order to do a procedure painlessly, but can also be done as a therapeutic measure to rest a nerve that's inflamed.

Motor/Sensory Block: Nerve block typically refers to a blockade of motor/sensory/sympathetic and/or parasympathetic pathways from a particular nerve (as opposed to an epidural that can block multiple nerves, or a plexus block that blocks more than one nerve). Usually a combination of local anesthetic (short or long acting depending on the reason for the block) and some adjunct agents are used (steroids, benzos, etc).