Jesus chose 12 specific disciples to be apostles, but what is the difference between the two?
The word "disciple" is only used in the Bible in the Gospels and the book of Acts. The word "disciple" means a pupil or a student of somebody. Of course, there are Jesus' disciples, but the followers of John and even the students of the Pharisee's were called disciples as well.
The word "apostle" means one who is sent on a mission or with a purpose. Jesus sent the apostles out on a mission with the purpose of spreading the Good News and starting the church.
According to the Bible while they were under the direct teaching and training of Jesus they would have been disciples. While Jesus had many disciples, only 12, with Matthias replacing Judas, were chosen to be His apostles.
"When morning came, he called his disciples to him and chose twelve of them, whom he also designated apostles: Simon (whom he named Peter), his brother Andrew, James, John, Philip, Bartholomew, Matthew, Thomas, James son of Alphaeus, Simon who was called the Zealot, Judas son of James, and Judas Iscariot, who became a traitor." Luke 6:13-16