/un'deuhr pin"/ , v.t., underpinned, underpinning .
1. to prop up or support from below; strengthen, as by reinforcing a foundation.
2. to replace or strengthen the foundation of (a building or the like).
3. to furnish a foundation for; corroborate: The author's conclusions are underpinned by references to experimental findings.
[ 1515-25; UNDER- + PIN ]