The Collaborative International Dictionary of English v.0.48:

Roble \Ro"ble\, n. [Sp., oak.] (Bot.)
   The California white oak (Quercus lobata).
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

roble
    n 1: large tree of Trinidad and Guyana having odd-pinnate leaves
         and violet-scented axillary racemes of yellow flowers and
         long smooth pods; grown as a specimen in parks and large
         gardens [syn: roble, Platymiscium trinitatis]
    2: tall graceful deciduous California oak having leathery leaves
       and slender pointed acorns [syn: California white oak,
       valley oak, valley white oak, roble, Quercus lobata]