'Ministry' comes from the Greek 'diakoneo', meaning 'to serve'.
Christian ministry means lovingly serving the needs of your neighbour with humility and devotion to God. In our modern world the term has been limited by some to mean only those in a vocational ministry, e.g. pastors; whereas in truth it is the duty of every Christian to serve one another with love and joy. Ministry is not a vocation, but a lifestyle, which can be followed in any calling.
Scripture to consider: Matthew 20:26, 28; Romans 1:1; 1 Peter 4:11