Teacher is a general term for instructors, associate professors, assistant professors, and professors. Professors are teachers of higher rank often with doctorate degrees. I had an instructor in college who didn't like to be called professor because he said he doesn't deserve the title. Then on another occasion, my philiosophy professor got offended after my classmate addressed him as teacher. He said it's too derogatory on his part. To play it safe just call them miss, ma'am, or sir. Good luck! :)

As for me, I usually call my college teacher as professor, sir, miss. And you may call them Mr...., Ms..., or Mrs.....

Hope it helpful to you.^^

Teacher is an occupation.

You may call them Professor, Sir, Mr., Mrs., or Miss.

Call your teacher in high school by their name. Calling them teacher would be kind of weird. In college you can call your teacher Professor "Last Name"