What is the difference between respect and aspect as nouns ?

Hi. What do you mean? These words have different meanings.  

Oxford says:
respect
3 a particular aspect or detail of sth:
In this respect we are very fortunate. Ç There was one respect, however, in which they differed.

aspect
a particular part or feature of a situation, an idea, a problem, etc.; a way in which it may be considered:
The book aims to cover all aspects of city life. Ç the most important aspect of the debate Ç She felt she had looked at the problem from every aspect. Ç This was one aspect of her character he hadn’t seen before.

So here lies a problem. Aspect is a countable noun, and respect is also a count. noun, too. But what the difference in these meaning lying above?

With regard to those two definitions from Oxford, think of respect as way; think of aspect as way of looking at something or way of considering something.

In this [respect / way] we are very fortunate.  There was one [respect / way], however, in which they differed.

The book aims to cover all [aspects of / ways of looking at / way of considering] city life.  The most important [aspect of / way of considering] the debate.  She felt she had looked at the problem from every [aspect / way of looking at it / way of considering it].  This was one [aspect of / way of considering] her character he hadn't seen before.

Note how common aspect of is.  respect is not as commonly used with of.

CJ