What does the word girder mean?

Usage examples for girder

  1. Morey, will you cut the rope in three equal pieces while I help Wade tear loose that girder? – The Black Star Passes by John W Campbell
  2. The Boyne was bridged, and everything that has since happened has but added a new stay or girder to the strength of the bridge. – The Open Secret of Ireland by T. M. Kettle