Definition of Armco in US English:



  • A very pure soft iron, used in particular for roadside guardrails.

    • ‘First obstacle will be the causeway itself with weed and branches clogging the under-bridge waterway so that it flows over the low-level bridge against the Armco, smashing it and flooding the road.’
    • ‘Lauda's Ferrari spun out of control and hit the Armco barrier on the inside of one of the circuit's many corners.’
    • ‘Mental note: a friend of mine wrote his Porsche off here… with me in it, so I'm hoping Kevin's careful on the exit as there's not much room between the rumble strip and the Armco.’
    • ‘It does have its difficulties, no run off areas, tight Armco, an interesting track surface with gutters and manhole covers, but with Monaco, they don't really bother you.’
    • ‘Other safety advances include improvements to marshal posts, new gravel traps and Armco fencing around the circuit.’
    • ‘Rather than having the usual run-off areas, the Armco barriers line the edge of the track itself so any slight error is likely to mean the end of your race.’
    • ‘I went into the Armco barrier on the left-hand side, which caused quite a lot of damage to the car.’
    • ‘There being no catch fencing or Armco to deflect him, he died from hitting a tree.’


Early 20th century: acronym from American Rolling Mill Company.