What does the FM, NM, and GM mean and how are they ranked?

im guessing the GM is grand master but have no idea the others. Also how does one go about achieving these titles?

I also see IM and CM. Any help with this would be greatly appreciated.

https://en.wikipedia.org/wiki/Chess_title

Thanks, that was an interesting article.

CM = Candidate Master. Requires 2200 rating.

FM = FIDE Master. Requires 2300 rating.

IM = International Master. Requires 2400 rating and 3 "IM norms".

GM = Grandmaster. Requires 2500 rating and 3 "GM norms".

There always has existed exceptions to the posted "requirements." Not hard and fast rules.

For example:

The World Junior Champion's - Men's and Women's

Originally the winner was awarded the title International Master if he had not already received it. Currently the winner receives the Grandmaster or Woman Grandmaster title, and the second and third-place finishers receive the International Master or Woman International Master titles.

IM and GM Titles are lifetime titles. Ratings may fall below the standard, but never results in the lose of the title.