hearse
轀 centers on a vehicle used for carrying the dead: a hearse. Its meaning is narrow and concrete, with no clear abstract extensions.
轀 combines 車 (vehicle) with 昷 (a component associated with warmth or covering), likely as a phono-semantic compound where 昷 hints at the sound and the idea of enclosing, as a hearse encloses the dead.
The left side 車 is a vehicle, and the right side looks like a person 人 over a mouth 口 over a dish 皿, suggesting a covered container. Picture a vehicle carrying a covered container for the deceased: a hearse.
For オン, imagine turning on the engine of a solemn hearse: on -> オン, as the vehicle slowly moves forward.