The Collaborative International Dictionary of English v.0.48:

Derivable \De*riv"a*ble\, a. [From Derive.]
   That can be derived; obtainable by transmission; capable of
   being known by inference, as from premises or data; capable
   of being traced, as from a radical; as, income is derivable
   from various sources.
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         All honor derivable upon me.             --South.
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         The exquisite pleasure derivable from the true and
         beautiful relations of domestic life.    --H. G. Bell.
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         The argument derivable from the doxologies. --J. H.
                                                  Newman.
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WordNet (r) 3.0 (2006):

derivable
    adj 1: capable of being derived