A Soffit by Any Other Name
According to Merriam-Webster, sort of maybe:
Main Entry: sof·fit
Etymology: French soffite, from Italian soffitto, from (assumed) Vulgar Latin suffictus, past participle of Latin suffigere to fasten underneath -- more at SUFFIX
: the underside of a part or member of a building (as of an overhang or staircase); especially : the intrados of an arch
The underside of a structural component, such as a beam, arch, staircase, or cornice.
I really hate not knowing what to call something. Saying "those thingies made of drywall above the cabinets" is not very efficient.