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]

The Collaborative International Dictionary of English v.0.48:

Reenforced concrete \Reenforced concrete\
   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.

   Syn: reinforced concrete. [Webster 1913 Suppl. +PJC]

The Collaborative International Dictionary of English v.0.48:

Ferro-concrete \Fer"ro-con"crete\, n. (Arch. & Engin.)
   Concrete strengthened by a core or foundation skeleton of
   iron or steel bars, strips, etc. Floors, columns, piles,
   water pipes, etc., have been successfully made of it. Called
   also armored concrete steel, and most commonly reenforced
   concrete.
   [Webster 1913 Suppl. +PJC]