Jochen —, F1 motor racing driver; 1975 Spanish GP winner (4)
I believe the answer is:
mass
(Other definitions for mass that I've seen before include "Quantity; religious service" , "congregate for > service" , "Substance; a service" , "Rite; quantity of matter" , "what 13 15A [STANDARD MODEL] supposes 12 [HIGGS BOSON] gives other 5A [PARTICLES]s" .)