他大学时的专业是国际贸易。 He majored in international commerce in college.
专业人员的助手受过训练辅助专门人员的非专职人员 A trained worker who is not a member of a given profession but assists a professional.
医术，医业，医学有关医学的技术和专业 The art or profession of medicine.
从业者，执业者从事某事的人，尤指从事职业、专业或技术的人 One who practices something, especially an occupation, a profession, or a technique.
许多人能够回答他们各自专业方面的问题，但是真正能区别人的智能还是一般常识的问题。 Many people can answer questions on their own special subject, but it's general knowledge questions that separate the men from the boys.
