Pastor, Priest, Bishop, Elder

Hard to believe but the four terms Pastor, Priest, Bishop, and Elder are all used interchangeably in the NT to describe the same function/office.

Pastor
The English word Pastor is only used once in the KJV:

Eph 4:11 It was he who gave some to be apostles, some to be prophets, some to be evangelists, and some to be pastors and teachers,

The Greek word used is ποιμενας poimenas, or shepherd. Matt 9:36 uses this same Greek word:

Matt 9:36 But when he saw the multitudes, he was moved with compassion on them, because they fainted, and were scattered abroad, as sheep having no shepherd.

Priest
The English word Priest is mostly used in the Old Testament. The KJV does not use the word Priest in the NT to specifically refer to Christian ministers although all believers are described as being part of the holy priesthood.

1Pet 2:5 Ye also, as lively stones, are built up a spiritual house, an holy priesthood, to offer up spiritual sacrifices, acceptable to God by Jesus Christ.

Bishop
The Greek word is επισκοποις or episkopois. It is a different office than that of deacon. Paul addresses both bishops and deacons as distinct:

Phil 1:1 Paul and Timotheus, the servants of Jesus Christ, to all the saints in Christ Jesus which are at Philippi, with the bishops and deacons:

Elder
The Greek word is πρεσβυτερους or presbuteros. The English word priest is cognate for this Greek word. This seems to be the same office as bishop. It has the same list of requirements. At the direction of the Lord, Paul went into each church that he had previously preached and ordained elders.

Acts 14:23 And when they had ordained them elders in every church, and had prayed with fasting, they commended them to the Lord, on whom they believed.