Hi to All,
Teacher or coach. Is there a difference?

There may be a strict definition, but in my experience, your teacher is your regular instructor with whom you, or you and your partner practice regularly vs. a coach is someone the studio brings in on a sporadic basis (often world-class) to elevate your technique, or help with choreography, or just bring a fresh and different perspective to your dancing. If you are just starting out, the coach will work with you and your teacher together. Coaches are usually prior chmpions who are now judging and teaching (and travelling extensively...therefore not affiliated with any one studio). If you are serious about competetive dancing, it's worth finding a studio that attracts these coaches on a regular basis.

Guest, I usually call that a visiting coach.

Top dancers often have what they call both trainers and coaches. Trainers help them with technique, choreography, etc at lessons which the dancers go to. Coaches have a more personal hand in things helping the dancers with their careers, the mental aspects, picking competitions, along with giving lessons.

Yes, but if iluv2dance is asking the difference between a teacher and a coach, he or she is probably not dancing at your level. (His or her teacher may be...in which case the teacher may be using trainers and coaches...but that's a little different.) I'm guessing you're a top level amateur?