DISCIPLE
He who follows a prophet, teacher, etc. is taught by him and is a supporter of this teaching (cf. Is. 8:16; Mt. 10:24; Mr. 2:18).
Thus the twelve apostles are called disciples (Mt. 10:1), as is another larger group of followers of Jesus (Jn. 6:66; cf. Lk. 10:1-12)
The charge in Mt. 18:19 literally says: make disciples of all peoples. In Acts, up to 21:16, all adepts (including women) are called disciples of Jesus.
Many norms of the Gospels that some believe are intended only for some are, on the other hand, valid for all Christians (John 13:35, for example).