A transport is a device that handles a particular physical storage medium (such as magnetic tape, audio CD, CD-R, or other type of recordable media) itself, and extracts or records the information to and from the medium, to (and from) an outboard set of processing electronics that the transport is connected to.
A transport houses no electronics itself for encoding and decoding the information recorded to and from a certain format of media. It only extracts and records information to the media, as well as handling mechanical operations for accessing the media itself, such as playing or rewinding a tape, or accessing the tracks on a disc.
An example of a transport for a storage medium would be an audiophile-grade audio CD transport, which houses no digital-to-analog converter (DAC), unlike most ordinary audio CD players. Instead, the audio CD transport is connected to an external DAC via a coaxial (SPDIF) or optical (Toslink) digital audio connection to convert the digital audio information to analog for interfacing to most audio equipment.
Other examples of transports for recorded media include: