Creating an array of user-defined structs

[brian via Digitalmars-d-learn]

On Monday, 22 August 2016 at 06:19:00 UTC, Mike Parker wrote:
> Terminology wise, we distinguish between associative arrays 
> (AA) and arrays. The former should never simply be called 
> 'array', otherwise people will assume you are referring to 
> either or both of foo[] (dynamic array/slice) or foo[N] (where 
> N is an integer constant, a static array). Change your title to 
> 'Creating an AA of user-defined structs' and the 
> misunderstanding goes away.

That's a terribly confusing naming convention for beginners then! 
:P
Is this D-specific terminology, or is this a more general 
convention that AA are not actually arrays?
This might help my understanding of when to use or not use one or 
the other. :)