There is no ritual meal on the 14th, the meal occurs on the 15th because the Jewish day starts at the beginning of the evening. The lamb is sacrificed in the afternoon when it is still the 14th and is eaten the same evening, when it is the 15th.
I've modified my post, having checked in Leviticus 23 where the initial Passover meal is described as taking place on the evening of the 14th day of Nisan.
The Feast of Unleavened Bread refers to the whole of Passover from 15th Nissan to 21st Nissan
My point was that "The Passover" can also refer to the entire festival, as it does in Luke 22:1, and also John 13:1. So it also could in John 19:14.
No it doesn't, it primarily refers to 14th Nisan which is not always a Friday.
"Paraskeue tou pascha" is only ever used once, so you have no way of confirming that it refers to that. It would be more accurate to interpret the phrase in the light of the established meaning of "paraskeue". *(See below)
Regardless, I should have said that "paraskeue" primarily refers to Friday. I've corrected my post.
The Paschal lamb is sacrificed on the 14th. "Paschal" derives from the Jewish word "Pesach" which is the real name of Passover.
I agree, but this does not rule out the possibility that the meal the priests were anxious to be able to eat was the one that took place during the day on 15th Nisan.
*Edit: The six occurrences of paraskeue are:
Matthew 27:62: "that followed the day of the preparation, the chief priests and"
Mark 15:42: "was come, because it was the preparation, that is, the day before the sabbath,"
Luke 23:54: "And that day was the preparation, and the sabbath drew on."
John 19:14: "And it was the preparation of the passover, and about the sixth"
John 19:31: "therefore, because it was the preparation, that the bodies should not"
John 19:42: "because of the Jews' preparation day; for the sepulcher was"
There seems little doubt that all five occurrences other than John 19:14 are basically telling us that it was Friday, because the bodies had to be taken down. This establishes the primary meaning of paraskeue.