Teaching is the way one person, who knows more, helps another, who knows less, to learn.

How that help is offered varies. Teaching styles range from the autocratic to the facilitative; teachers can see themselves as pedadogues and pontificators, motivators and encouragers, or just another kind of learner.

There are many different words for teachers. Some emphasise the similarity between teachers and learners, others emphasise the differences between them.

At one extreme is the author. He (or she) may know or care little about his readers. At best he has some vague, generalised individual in mind when he writes.

At the other are learners themselves, who see each other as being the same kind of animal, though their abilities may differ.

Between to two is a kind of heirarchy - author, lecturer, instructor, trainer, teacher, tutor, guru, coach, mentor and learner - down which closeness, contact and identification with the learner, slowly increases.

Similarly, some of these terms imply more formality than others. Both lecturing and instructing would be seen as more formal than coaching or mentoring.