Often a source of confusion is the .cda file. On a windows computer, when you insert a RedBook Audio CD, the tracks show up as .cda files. One might assume that these are the audio files on the disc because they are the only items that show up in the explorer window. . . that would be wrong. The .cda files are merely placeholders pointing to a place on the CD that the song starts. Think of them as what windows calls a 'shortcut'.
Yellow Book is the name given to the data compact disc (a common CD-ROM) format. Its name comes from the series of books, also called the 'Rainbow Books' that define all compact disc formats. It was developed by the creator of the compact disc, Sony/Phillips, and is now one of the most common CD formats.
PQ codes are the first 2 of 8 sub-channel information encoded on a 'Red Book' CD.
Red Book is the name given to the compact disc digital audio format.
A master is a data storage device that transports the final recorded product to the replication plant. The two most common formats today are Red Book PQ-Masters and DDP Masters.