As I read both English and Russian chess literature I run into the term 'master'. It is clear from the context that is below grandmaster but is somehow given much respect. I never know what it actually means because it could be any of the three or even something else: FIDE Master, International Master, National Master (whose meaning depends on the country).
This site has many questions about 'master strength' so it is part of everybody's jargon. But I really don't know what it means.