「教師(きょうし)」：A teacher at a school or university.
自己紹介や職業名を書くときに使います。
It is used when introducing yourself and writing your professional name.
「先生(せんせい)」：A teacher at a school or university, or a profession (doctor, politician or lawyer).
相手を呼ぶときに使います。
It is used to call someone by their name.
e.g.「たなか先生(せんせい)」
or just 「先生(せんせい)」
自分のことを「教師」とは言いますが、「先生」とは言いません。
However, unlike「教師(きょうし)」, you do not call yourself「先生(せんせい)」.
The word 「教師(きょうし)」 and 「先生(せんせい)」are similar in meaning, but there are differences. Pay attention to the differences and remember them.
