The story
The noun is derived from shock + stall (“loss of lift due to an airfoil’s critical angle of attack being exceeded”). The verb is derived from the noun.
Etymology from Wiktionary, CC BY-SA 4.0.
shock stall
Today it means: A stall (“sudden loss of lift”) caused when the airflow over an aircraft's wings is disturbed by shock waves that occurs at a specific Mach number when the aircraft is accelerating to transonic speeds. Full definition →