physical education teacher; PE teacher; gym teacher
Refers to a teacher who instructs physical education classes at a school.
The PE teacher leads radio calisthenics in the schoolyard every morning.
She majored in exercise physiology at university to become a PE teacher.
体育 means 'physical education' as a subject or activity, while 体育教師 specifically refers to the teacher.
教師 is a general term for 'teacher', whereas 体育教師 specifies the subject area.
Compound of 体育 (physical education) and 教師 (teacher). The exact historical derivation is straightforward; the word follows standard Sino-Japanese compounding patterns.