Biff wrote...
....
Where did I claim blank means cells evaluating to ""?

A blank cell can contain
a formula that returns "nothing"

That's why "nothing" is quoted!
....

You wrote: "The "problem" arises when people use the 2 terms
interchangeably. An empty cell is one that contains nothing, nothing at
all. A blank cell can contain a formula that returns "nothing" so the
cell is not empty, it contains a formula but the cell appears to be
empty."

You may have been imprecise in your definition of 'blank', but your
definition of 'empty' is the definition of 'blank' (in the ISBLANK
sense), so by stating that 'blank' means something else you're wrong.

Simple linguistics would imply most people would draw a correspondence
between 'blank' the state and ISBLANK the function. If so, 'blank'
means the state in which cells contain nothing (no quotes). Some other
term, perhaps 'empty', could be used to refer to cells with no visible
result (I tend to use 'visually blank').