The catalog number is the number that retailers and distributors use to
order the recording.
The matrix number is the number used internally by the manufacturing plant
to keep track of the specific metal parts used, labels, etc.
There is also a master number that is inscribed in the master by the
mastering engineer. (I was a mastering engineer at Motown records during the
mid 1960s.) This generally relates to the master tape used.
In many cases this master number would also be used as a matrix number while
in others an additional number would be assigned to identify the particular
metal parts used. This was pretty much up to the pressing plant. At least
three different regional pressing plants were generally involved in any
national release because of the cost of shipping records.
Bob Olhsson Audio Mastery, Nashville TN
Mastering, Audio for Picture, Mix Evaluation and Quality Control
Over 40 years making people sound better than they ever imagined!