In the United States, teacher is usual from pre-K through high school, while professor often refers to a college faculty member. Instructor is broader and may be a job title or describe someone teaching a course or skill.
The words overlap, and each school may use titles in its own way.
When do Americans say “teacher”?
Americans usually call someone at an elementary, middle, or high school a teacher:
"My son's math teacher emailed us."
"She was a high-school teacher before moving into corporate training."
College students may also say teacher in casual speech when the exact rank does not matter. However, Teacher Smith sounds odd at most U.S. colleges.
When do Americans say “professor”?
Professor often describes someone who teaches at a college, but it can also name a formal rank. Examples include assistant professor, associate professor, and professor.
A student may address an instructor as Professor Lee even when the person's formal rank is different. Each school and field has its own norms, so follow local custom.
If the person has stated a preference, follow it:
"Please call me Dr. Lee."
"Professor Lee is fine."
Not every professor has a doctorate, and not everyone with a doctorate is a professor.
What does “instructor” mean?
Instructor focuses on the teaching role and may be an official college job title. Its duties vary by school.
Outside universities, instructor is common for skills-based learning:
- driving instructor
- fitness instructor
- flight instructor
- corporate-training instructor
- workshop instructor
At work, facilitator, trainer, coach, and instructor may name different roles whose meanings depend on the employer.
A lot to take in? It is.
But Rome wasn't built in a day. Build your American workplace English one expression and cultural reference at a time—with curated explanations and structured practice in Lyra Practice.
Start a session →What might you hear at work?
"My professor connected me with this internship."
The speaker probably means a college teacher.
"I need to attend a parent-teacher conference."
This is usually a K–12 meeting with a parent or guardian.
"The instructor will send the course materials tomorrow."
This could mean a college class, company workshop, or certification course.
"She joined us from the faculty of a business school."
Here faculty may mean teaching staff or a school division. U.S. listeners may need more context for the second meaning.
"He is an adjunct professor."
Adjunct usually means a teaching job outside the tenure track and is often part-time, but job terms vary by school.
What can you say naturally?
For workplace small talk:
"I used to teach high-school science."
For networking:
"One of my university professors introduced me to the field."
For training:
"The instructor has ten years of experience in cloud security."
If you are unsure how to address someone:
"How would you prefer to be addressed?"
In email, use the title in the person's signature, staff page, or course notes. Dr. fits someone who uses it, but it does not always replace Professor.
What should you put on a résumé?
Use the title that matches your role:
"High School Mathematics Teacher"
"Adjunct Instructor, Business Analytics"
"Corporate Training Facilitator"
Do not change instructor to professor just because both teach adults. Only the institution can grant an academic rank. A false title can hurt trust.
If your title comes from another country, use its official English version; a short note may help:
"Lecturer (full-time university teaching appointment)"
Recognition versus production
For my teacher, age and context help show the school level. An adult saying my professor probably means college. My instructor stresses the teaching role, not the type of school.
Choose the narrowest true label and check the formal title when the job matters. This is important for hiring, fact checks, and staff bios.
Avoid status assumptions
These titles may signal status, but they do not measure teaching quality. A K–12 teacher, college professor, and technical instructor do different work. Their training and job rules also differ.
Work terms vary, so do not infer pay, tenure, job security, or degrees from a title alone. A neutral question is:
"What do you teach?"
rather than:
"Are you a real professor or just an instructor?"
For group nouns, see faculty, staff, and student body meaning. For course terms, see class versus course in American English.