The Gospels say it was the day of preparation, or Paraskeue, which was the ordinary word for the sixth day of the week (i.e. Friday).
Right, and Jesus said he desired to eat the Passover with his disciples before he was taken that night. The “Last Supper” was the night of the Passover. That would have been after six o’clock (our Thursday night, but the beginning of the next Jewish day (ie. Friday)) so the new Jewish day would have already begun which would have been the same day as the day of preparation both the day before the sabbath, Saturday.