Should "occupant impact with the airbag" be written as:

"occupant airbag impact" or "airbag occupant impact"?

And should "interaction between occupant and airbag" be written as:

"occupant airbag interaction" or "airbag occupant interaction"

  • 1
    Impact is a noun in this construction. Probably three nouns in a row is overkill, and a preposition is a good thing to separate a them. In other words, occupant impact with the airbag shouldn't be written either way you suggest -- it's fine the way it is. Commented Oct 9, 2016 at 15:45
  • Thanks John Lawler. Even if three nouns in a overkill, is using three nouns right grammatically? If so, which combination of the three nouns is right? And well, I'm not a native english speaker, please correct me. Commented Oct 9, 2016 at 15:58
  • Noun compounds are not a matter of grammar but of fixed phrasing. The more nouns you put together, the more possible meanings there are. The prepositions are necessary to keep the meaning; if you take them off, you can't predict how other people will understand a particular stack like occupant airbag interaction, especially if it's something they're unfamiliar with. That's only if you're interested in being understood, of course. Commented Oct 9, 2016 at 16:05
  • You can also show the more cohesive or more truly coordinated pairing by using a hyphen: occupant-airbag impact. Commented Oct 9, 2016 at 21:00
  • I would use a slash: occupant/airbag impact. Commented Oct 10, 2016 at 7:36

1 Answer 1


In each of the examples, I'd consider the first two words as a compound modifier of the third word. As such, I'd hyphenate them:

  • occupant-airbag impact
  • occupant-airbag interaction

It's hard to find one web citation that covers this situation. But see http://www.grammar-monster.com/lessons/hyphens_in_compound_adjectives.htm for hyphenating compound adjectives, and http://grammarist.com/grammar/nouns-as-adjectives/ for using nouns as adjectives.

A common example that fits the same pattern of three nouns in a row (where the first two are a compound which modifies the third) would be the "wave-particle duality" of light: https://en.wikipedia.org/wiki/Wave%E2%80%93particle_duality https://www.sciencedaily.com/terms/wave-particle_duality.htm

I don't think the order of the first two words matters: "Whether the stone hits the pitcher, or whether the pitcher hits the stone, it's going to be bad for the pitcher." That's certainly true for the "interaction." If you want to emphasize the object-vs.-subject of the "impact," then I think your only choice is to re-word the sentence to make that explicitly clear.


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