Monday is one of the nineteen Records. It is a record that plays the music when Jennifer is exploring the Airship for the first time during the "Unlucky Clover Field" chapter. It is used on the record player in the Reception Room of the Rose Garden Orphanage.
It can be found, using the Sunday record, in the cafeteria at nighttime in "The Funeral" chapter. It can later be used to find the Tuesday record.