Meaning of prestress

pre•stress

Pronunciation: (prē-stres'), [key]
— v.t.
  1. (in certain concrete construction) to apply stress to (reinforcing strands) before subjecting to a load.
  2. to make (a concrete member) with prestressed reinforcing strands.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.