What do different professor titles mean?

Hi everyone!
I am a high school junior doing a lot of research into violin professors right now and am really confused by all the different titles for professors. There are assistant and associate professors and then some are lecturers. What do these different titles mean? Is it just related to their pay/tenure or if someone is an assistant professor or lecturer, can I not study with them?
Thank you!

Professor
Associate Professor
Assistant Professor
That is the hierarchy of tenued/tenure track faculty.

Lecturer or Adjunct Professor are part time non-tenure track faculty.

You will have all titles teaching you.

Professor and Associate Professor positions are tenured while Assistant Professor is on tenure-track. Lecturer or Adjunct Professor, as TomSrofBoston pointed out, are non-tenure track faculty. They all teach, and you can take classes with any of them.

Lecturer and Adjunct Professor positions tend to make very little money and so often seen as a temporary positions. Often, Assistant Professor moves on, too, either unable to secure tenure at the current institution or because of better prospect of receiving a tenure position elsewhere.

Therefore, you’d have to be careful not to select any particular institution for one particular faculty. It could happen that, by the time you commit to enroll, the faculty might have moved on or moving on to another institute. The faculty in music schools and conservatories seem to be more mobile than other disciplines even for those with tenure.

If you have a very strong desire to work with any one particular faculty, you should, before making a full commitment to enroll, communicate with the faculty about his or her own commitment to the institution and any career plans down the road.

Thank you @TiggerDad and @TomSrOfBoston, that really helps!

I work at a major university on the West Coast, and I’d concur with much of the above, but I think Lecturer/Adjunct positions need additional commentary.

Depending on your instrument and/or major, prominent faculty members will often be Lecturer and/or Adjunct. This includes orchestra members and/or touring musicians. It is impractical for them to devote the time the university would demand to be a full-time faculty member. Don’t assume that Lecturers/Adjuncts are temporary. Look at what their “day jobs” are, and if they are tenured players in the local professional orchestra and have held their part-time positions at the same university/conservatory for some time, the odds are pretty good that they’ll be around for a while.