The Collaborative International Dictionary of English v.0.48:

Reinforced concrete \Re`in*forced con"crete\
   Concrete having within its mass a system of iron or steel
   supports, such as bars, rods, or a heavy mesh, to provide
   increased tensile strength and shear resistance. Same as
   Ferro-concrete. [Also spelled reenforced concrete.]
   [Webster 1913 Suppl. +PJC]

WordNet (r) 3.0 (2006):

reinforced concrete
    n 1: concrete with metal and/or mesh added to provide extra
         support against stresses [syn: reinforced concrete,
         ferroconcrete]