heavy bombers reached their ceiling, i think with the b-52. developing new bombers, as far as i can see, is a criminal waste of resources, post Cold War.
Radar Cross Section
RCS: Radar Cross Section - how big of a reflection an object makes at radar wavelengths.
RCS -> Radar cross section
RCS = Radar Cross-section (a bit more field-specific, more or less how "big" the thing looks on radar, but it is a bit jargony -- it depends on things like the material and radar wavelength).