from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A rod or bar used for reinforcement in concrete or asphalt pourings.
- n. A group of such rods forming a grid.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A steel reinforcing bar in a reinforced concrete structure.
- n. A grid-shaped system of such bars.
re(inforcing) bar.(American Heritage® Dictionary of the English Language, Fourth Edition)
Blend of reinforcing and bar (Wiktionary)