[1] : The Collaborative International Dictionary of English v.0.48

underpin \un`derpin"\, v. t. imp.  p. p. underpinned; p.
   pr.  vb. n. underpinning.
   1. to lay stones, masonry, etc., under, as the sills of a
      building, on which it is to rest.
      1913 webster

   2. to support by some solid foundation; to place something
      underneath for support.
      1913 webster
see also:
underpinned underpinning 

[2] : WordNet (r) 2.0

underpin
     v 1: support from beneath
     2: support with evidence or authority or make more certain or
        confirm; "the stories and claims were born out by the
        evidence" syn: corroborate, bear out, support
     also: underpinning, underpinned
see also:
corroborate bear out support underpinning underpinned 

Underpin >> U Words
Underpin, definition of term: Underpin
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