Students who are new to the New Testament are frequently confused by some of the terms used throughout the text. Why are the men who were called the Twelve Disciples in the Gospels now called Apostles in Acts? What are Deacons and how do they fit in? Why is the term "Christian" not used until Acts 11, and then rarely used again? What did Christians call themselves?
I hope the following definitions will help you as you read the New Testament:
Disciple - Our word disciple comes from the Latin word discipulus which means "student." It was common during Jesus' day for Jewish rabbis (which is how most of Jesus' early followers would have thought of Him) to have an entourage of disciples who would act as a sort of "road crew" for their master as he traveled the countryside teaching. They would prepare meals, find lodging, manage donations and perform all the menial tasks required for a successful tour.
In exchange, the disciples were treated as apprentices, entrusted with personalized instruction not available to the masses, and given opportunities to teach and share in the ministry in the hope that they would one day become rabbis themselves. We commonly talk about Jesus' twelve "core" disciples, but He almost certainly had more (converts like Zacchaeus, as well as Mary, Martha and Lazarus likely would be called themselves disciples of Jesus).
Before ascending to heaven, Jesus told His disciples that now they were to go out into the world to make more disciples. While these disciples wouldn't follow Jesus literally - carrying his luggage around the Judean countryside like the Twelve had done - they were to be taught to "obey all the commands" Jesus had given them during His ministry. These new disciples would still seek to follow the example of their master, to become like Him and to build His Kingdom.
Because of this, the term disciple can refer to the Twelve Disciples during Jesus earthly ministry, or to any follower of Jesus - then or now. In fact, to call yourself a Christian is to claim to be follower - a disciple - of Jesus.
Apostle - The English term apostle comes straight from the Greek (the original language of the New Testament). In Greek, the word literally means "someone who is sent out" - what we today would call a missionary.
This is why the Twelve Disciples of the Gospels are referred to as the Twelve Apostles in the book of Acts. After Jesus' resurrection, they are no longer mere disciples (students), they have been commissioned - "sent out" to spread the gospel. This term apostle is also used to describe men like Paul, Barnabas, Silas and others who were not part of the original Twelve, but are sent out as missionaries.
Christian - It is often surprising to readers of the New Testament that the word Christian is only used three times in scripture. The word comes from the Greek Christianos - the name Christ with the diminutive suffix -ian added to the end of it. Literally translated, it means "Little Christ" or "Christ-ling" and was originally used by nonbelievers as an insult. Followers of Christ, much to the annoyance of their mockers, became fond of the term, and it eventually stuck.
This begs the question - if Christians in biblical times didn't describe themselves as Christians, then what did they call themselves?
To answer this question, it is important to understand that, at least for the first few decades of the church, followers of Christ didn't think of themselves as a separate religion. Peter and the Apostles would have thought of themselves as Jews (because they were) following the promised Jewish messiah. They weren't following a new god; they were following the God of Abraham, Isaac and Jacob. It wasn't until the destruction of Jerusalem in 70 A.D. that Christians began to see themselves as truly separate from the Jewish tradition from which they emerged.
Because of this, these believers weren't quick to adopt a new name for themselves. Acts often refers to Christians merely as "believers." On a few occasions, it talks about the early Christian movement as "The Way" and to Christians as "followers of the Way" which was likely the term that Christians during the 1st century used to describe themselves.
Church - The New Testament word for "church" is ecclesia which means "those who are called out." This term was likely chosen for two reasons: the early Christians viewed themselves as "called out" of the world - and their Jewish heritage - in order to build the Kingdom of God. Ecclesia is also a common Greek word for "assembly," which adds a utilitarian bluntness to the theological implications.
Church Leadership - The New Testament, and particularly the letters of Paul, use several terms to describe various leaders within the church. The exact meaning of these terms - and even how they should be translated - are hotly contested by various denominations. Many Protestant denominations don't like translating episkopos as "bishop," while the Catholic church often translates presbyter as "priest," even though that term is anachronistic when applied to the early church.
Because of these controversies, I'll talk about each of these terms using their Greek names.
episkopos - Generally translated as "bishop" or "overseer," this church leader was entrusted with the responsibility of leading all the believers in a particular city. In the earliest days, these believers would have numbered in the dozens or hundreds and all met in one place, making the episkopos roughly equivalent to a "Senior Pastor" or "Priest."
As Christianity grew and the number of believers in large cities grew to number in the thousands, there were simply too many believers to meet all together. As a result, the duties of the episkopos became closer to what Catholic or Episcopal churches would call a bishop - an administrator who oversees a number of smaller congregations within a geographic area.
presbyter - Meaning "old man" and typically translated as either "elder" or "priest," (in fact, the English word priest is derived from it) the exact role of the presbyter is unclear. It appears that in the earliest days of the church, the term was used interchangeably with episkopos. By the time Paul wrote his letters to Timothy and Titus, the roles seem to have become distinct.
What is clear is that these presbyters were ranked somewhere between the episkopos and diakonos, and that each congregation had several of them. It is possible they served as secondary teachers or worship leaders - similar to modern Youth or Worship ministers.
By the second century, as the role of the episkopos in large cities expanded to that of a bishop, the smaller congregations within the city were each led by a presbyter.
diakonos - Deacons are first mentioned in Acts 6, though the term "deacon" is not used in Acts but comes from Paul's letters. Like other terms on this page, deacon comes to us straight from a Greek term: diakonos meaning "servant." That definition explains their original function perfectly; deacons were those chosen by the church to carry out mundane but important tasks such as caring for widows and orphans so that the Apostles and other church leaders could focus on preaching.
pastor - The term "Pastor" is not found in the New Testament, and is of Latin rather than Greek origin. Originally meaning "shepherd," pastor became a replacement for the term presbyter as Latin became the dominant language in the Western church.