@humy said
but that is what is generally meant by different "sizes" of black holes.

Read the OP.

The poster specifically said that they don't mean the size of the EH.

@suzianne said
Read the OP.

The poster specifically said that they don't mean the size of the EH.

but that is what is generally meant by different "diameters" of black holes either although that seems to depend on context and the particular literature.
The "diameter" of a black hole is usually taken to mean the diameter of its event horizon although on rarer occasions it can mean the diameter of its singularity. I have noticed that Wiki generally goes for the latter meaning but most albeit not all non-wiki websites I have so far read seem to go with the former meaning. Just one example;

https://curiosity.com/topics/how-big-or-small-can-a-black-hole-get-curiosity/
"...If it's not spinning, the diameter of a black hole is approximately 6 kilometers (3.7 miles) for each solar mass"

-obviously, they must mean the diameter of its event horizon above.