导师 (dǎo shī) literally combines 导 (dǎo), meaning 'to guide' or 'to lead', and 师 (shī), meaning 'teacher' or 'master'. Together, it refers to a senior academic who guides, advises, and supervises students—especially at the graduate level—in their research, coursework, and professional development. Unlike a regular teacher (老师 lǎo shī), a 导师 has a formal, long-term mentoring role and often oversees thesis or dissertation work.

The term is widely used in universities across China and other Chinese-speaking regions. It carries respect and implies authority, responsibility, and close intellectual collaboration. While primarily academic, 导师 may also appear in corporate training contexts (e.g., mentorship programs), but its core usage remains firmly rooted in higher education. Students typically address their 导师 formally and maintain a respectful, professional relationship.