Language is important; used with precision, it can clarify, but when words are used interchangeably, it can confuse or obscure. Through the history of CiS (now EDU) we developed the following clarification of vocabulary:
Coach – a chess player, usually with no knowledge of how to teach, who works with individuals or groups to develop their chess ability.
Instructor – a chess player or Coach (more rarely a Trainer) who ‘teaches’ chess. Sometimes, if accompanied by a Teacher, allowed into a school class, although many countries forbid this. Usually ‘teaching’ chess outside of normal school hours.
Lecturer – Someone approved by EDU to guide Teachers (also Instructors) through the EDU courses (School Instructor, etc.) so that they have a sufficient understanding of chess basics to teach that in their classes. Also used for the person who prepares candidates to be EDU Lecturers.
Teacher – a school (or pre-school) teacher who has followed a full-time course (usually 3 years), learning how to teach. Only Teachers have been trained to teach (aside from some rare individuals in the other groups who also have a teaching qualification)
Trainer – a chess player of great experience who (FST) can train Coaches to be better at their work or (FT, FI, NI, DI) who work with individuals or groups to develop their chess ability.