The term 'Nth Degrees' is used to refer to the highest level of academic achievement. Specifically, it is used to describe the highest degree a person can obtain in a particular field of study. For example, a person who has obtained a PhD in a certain field would be said to have achieved the 'Nth Degree' in that field. The crossword solutions for this term are 'Heights' (7 letters) and 'PhDs' (4 letters). Heights is a reference to the highest point or level that someone can reach, while PhDs is a reference to the highest degree a person can obtain in a particular field of study.