Now I'm confused. Are you saying that playing blue notes are basically a penatonic scale with a diminished fifth, or that blue note is a term for a flatted fifth or augmented fourth?

Don`t be cofused.
Theoretically, the flatted 3rd and flatted 7th, are known as minor intervals,
When you are soloing using the Blues Scale, those are the notes that you target; those plus the real blue note (diminished 5th).
Usually you target those notes using bends that are not exact semitones,
they are slightly less than a semitone.