subframe
/ˈsʌbfrɛɪm/Definitions
1. noun
A smaller frame or structure within a larger one, especially in a vehicle or a building.
“The car’s subframe was badly damaged in the accident.”
2. verb
To provide or form a subframe for (something), especially in a vehicle or a building.
“The engineer will subframe the new wing of the building with steel beams.”