What does the A stand for in Intellij IDEA?

Intelli ===> Intelligent

J ===> Java

Idea ===>IDE that is Advanced or Idea just means idea( I have a good idea ...like this ) ...

//The Idea has Double meaning

Maxim Shafirov (the CEO of JetBrains), made the following comment prior to 2005, in a now deleted official JetBrains news article, published online:

I have always thought that it's a play on words that (1) it's an IDE, and (2) "idea" is a nice sounding word which contains "IDE".

Reference:

https://intellij-support.jetbrains.com/hc/en-us/community/posts/206938805-IDEA-acronym-?page=1#community_comment_207115259

So, based on the only thing I've seen that looks like actual evidence, I think a good answer may be "it probably isn't intended to mean anything"

It stands for application, but is mostly a play on words giving the IDE's name a creative appeal by just turning the widely-used 'IDE' (Integrated Development Environment) into IDEA (like "I have a brilliant idea!").