Either have the name mean one thing, or have it mean
the other. Using the same name used for conflicting
definitions in the same field is just
counter-productive.
That isn't what is done. "Organism" means "individual living being" --
which, for multicellular organisms, happens to be a level of organization
above that of the cell and usually also above those of tissues and organs.
You seem to have taken this "special" case, misinterpreted it, and
generalized from that. That was my point.