In the New Testament, a disciple is simply a learner, someone who subscribes to the teachings of another. A disciple of Christ, then, was one who followed Christ to learn His ways in word and deed. Outside of the Gospels, only a handful of verses in the New Testament use the word.
In the purest sense, a disciple requires the physical presence of the Master. When Christ ascended into heaven, the original disciples became known as apostles, and new coverts were simply called believers, the predominant term in Acts and the Epistles. The term Christian was coined in Antioch (Acts 11:26). King Agrippa used this label (Acts 26:28) as did the apostle Peter (1 Pet 4:16).
Practically and theologically, there is little distinction between the terms. When used in the Christian context, disciple, believer, and Christian all imply trust in and obedience in Jesus Christ.
LUKE 22:39 – And he came out, and went, as he was wont, to the mount of Olives; and his disciples also followed him.