Definition from Wiktionary, the free dictionary
- Present participle of underpin.
underpinning (plural underpinnings)
- A support or foundation, especially as a structure of masonry that supports a wall or a metaphorical basis for something.
- This house's underpinning is not up to standard.
- I would like to know more about the underpinning of this political theory.
- Legs, more generally.