No hyphen needed here?

Language English Grammar & Usage
1

Hi,

Can I just confirm that I don’t need a hyphen between the numbers and nouns in this sentence:

BlockquoteWhen launching a 42 mm projectile, the overall mechanism is similar to that of a 17 mm projectile.

My thinking here is that as the word “projectile” here is a noun it is not a compound adjective like a “three-man tent” would be, and therefore no hyphen is needed. However, I have been wrong about these things before and would just like to check.

Any help would be appreciated.

Thanks

2

My first instinct is to put a hyphen between the number and the unit, since they’re a combined adjective (I don’t know the correct term):

“When launching a 65-mm projectile …”

I quickly googled and found a few examples of “a 65-mph speed limit”. But I also found examples without the hyphen.

3

I would use space or no space, but not hyphen for things like mm and cm, but it’s more a matter of style than any hard and fast rule.

4 Likes