Used by English speakers, "professor" is a title, usually a title of someone who works at a university. A "teacher" is anyone who teaches, it is a description of a job function. Many professors both teach and do research. Some professors only teach. Some professors only do research. Therefore, most professors are teachers, but not all. At a typical U.S. university, there may be "teaching assistants," "instructors," "assistant professors," "associate professors," and "full professors." All of these are teachers (except for the few professors who only do research) but not all are professors. A lecture is a formal talk given by a teacher to a class. It is usually part of a systematic series of lectures in a course that covers a specific topic. The teacher usually stands at the front of the room--a small classroom or a large lecture hall--talks to the students, writes on the blackboard, shows slides, asks and answers questions about what she has just said. A seminar is an informal discussion group, typically of half-a-dozen to a dozen advanced students and a professor, in a general subject area. The professor guides the meeting but does not present a formal lecture or cover a specific topic. The first meeting of the seminar might be a meeting to decide exactly what topic will be covered. The catalog might say "Seminar: Zoology," and the professor might say "This semester I thought perhaps we should look at some papers in tropical ornithology and discuss them." In the United States, I do not think there is a difference between "a dissertation" and a "a thesis." "Dissertation" is a formal term, "thesis" is an informal term. However, "dissertation" often means doctoral dissertation--a "Ph. D. thesis," whereas a master's thesis or an undergraduate thesis is not usually called a "dissertation."

A tutorial was a smaller group when I was at university. A professor is a senior teacher, a title given. A thesis is longer than a dissertation

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