A teacher is a male or female adult whose profession is the teaching of knowledge, behavior norms, arts, crafts, physical and intellectual skills to other people by means of verbal instruction, demonstration and media.
This process transports the knowledge, skills and cultural achievements of one generation to the next generation and is thus the key factor to cultural progress.
The art and science of teaching is also known as pedagogy.
The most common form of professional teaching is the teaching of children. For better efficiency, typically a teacher teaches not a single child but a group of children simultaneously, called a class. The rooms in which the class is seated for this purpose are called classrooms and the buildings and institutions of this teaching are called schools; the whole process of education in schools, which today has a typical minimum duration of 8 years, is known as schooling.
The history of schools reaches back to antiquity. The level of intellectual, cultural and economical achievement of a people was usually in direct proportion to its quality of schooling.
For a very long time only boys were educated by private teachers and in public or private schools, and the teachers were usually male as well. They were also referred to as schoolmasters. This has changed in the last two to three centuries; today in most countries girls attend schools the same as boys, and teachers can be either men or women. The terms schoolmistress and schoolmarm are female equivalents to schoolmaster.
The methods and techniques of teaching, as well as the subjects taught, have evolved slightly over the centuries since antiquity, and changed dramatically within the past century.
The stereotype of the schoolmaster as a punisher
For example, this old woodcut shows six "civic professions": clockmaker, schoolmaster, organ builder, painter, goldsmith, sculptor. Every man is depicted in doing his work, and the schoolmaster is depicted birching a student. For many more images on the cliche of the teacher as an instructor through the means of corporal punishment, and his inseparability from the birch rod, switch and cane, see School corporal punishment (antiquity-1699) and School corporal punishment (1700-1899).
The Schoolmaster, Gerrit Dou (1645).
Painting by Ambrosius Holbein.
Illustration by Jim Black (Luc Lafnet, 1929).
Other forms of teaching
Other forms of professional teaching include privately hired governesses, homeschooling, private institutions such as dance or music schools, coaching in sports clubs, university teaching and adult education.
Forms of semi-professional teaching include private lessons (usually in the afternoon or evening, after the regular school) and mentoring. Such semi-professional teachers are called tutors or mentors.
A frustrated music teacher uses a violin bow as a percussion instrument. Ostra Studio (c. 1930s).
The Ballet Lesson by Julian Guile.