Well, the first phrase that pops into my head when I hear the word "disciple" would be The Twelve Disciples. However, I also think of people who follow in Jesus's teaching by going out and teaching others about God, His grace, His love, His mercy, and His forgiveness. I suppose I think of preachers and missionaries more often than not because it's there career to do those things. Of course, we're all called to teach the gospel if we are believers in Christ. Jesus himself gave us that directive in Matthew 28:19-20.
It looks like I'm about to get off subject, so I'll just leave it at that.