expertise; academic skills; one’s studies 是故弟子不必不如师，师不必贤于弟子，闻道有先后，～有专攻，如是而已。(韩愈《师说》)A student is not necessarily inferior to his teacher;a teacher is not necessarily superior to his student.The difference between a teacher and a student is: The former knows Tao (i.e.Taoist doctrines) earlier and they each have their own expertise.(Discourse on Teaching by Han Yu)