An inducer is part of the transporter system.
After the USS Jenolin crashed into the surface of a Dyson sphere in 2294, Montgomery Scott and Matt Franklin were forced to store themselves as patterns in the ship's transporter system. Seventy-five years later, when Commanders William T. Riker and Geordi La Forge investigated the ship and rescued Scott, they discovered Matt Franklin's pattern had degraded and was lost, likely due to one of the transporter's inducers failing. (Star Trek novel: Engines of Destiny)