underpin
UK: ˌʌndəˈpɪn | US: ˌʌndərˈpɪn
vt. to support, strengthen, or provide a foundation for something (literal or figurative)
vt. to corroborate or justify a theory, argument, or claim
The word "underpin" combines "under" (Old English under, meaning "beneath") and "pin" (Old English pinn, meaning "peg or fastener"). Originally used literally in construction (e.g., supporting a structure with pins or beams beneath), it later evolved to metaphorical uses, such as reinforcing arguments or systems. The logic mirrors physical support: just as a pin stabilizes from below, evidence "underpins" a theory.
Steel beams underpin the ancient bridge to prevent collapse.
Her research underpins the new climate change theory.
Strong moral values underpin their community’s traditions.
The lawyer underpinned his case with solid evidence.
Economic stability underpins social progress.