archiereus

The word combines the prefix archi- (chief, highest) with hiereus (priest, ἱερεύς), designating the single highest-ranking priest of Israel's sacrificial system. In Second Temple Judaism this was the one man authorized to enter the Holy of Holies once a year on the Day of Atonement, to offer sacrifice for the whole nation, and to preside over the Sanhedrin. The office was in theory hereditary (from the line of Aaron), but by the first century Rome appointed and removed high priests, making it a position of both religious authority and political power.

In the Gospels and Acts the word functions in two distinct registers. In the singular it names the reigning officeholder: Caiaphas during the trial of Jesus, Annas as his powerful father-in-law who retained informal authority, Ananias before whom Paul appeared. In the plural it designates the broader priestly aristocracy, the former high priests and their close kin who formed the ruling party within the Sanhedrin. These "chief priests" appear repeatedly alongside the scribes and elders as the organized leadership that opposed Jesus, authorized his arrest, and pressed for his execution.

Hebrews applies the title to Jesus in a theologically distinct way, presenting him as the one perfect high priest whose single self-offering fulfills and ends the entire sacrificial system. The argument runs through the center of the letter: Jesus is both priest and sacrifice, entering not an earthly sanctuary but the very presence of God, and he holds the office permanently rather than passing it from one mortal to the next.