What is the proper term for the area of a cross section? I am looking at these two formulations:

  • cross-section area
  • cross-sectional area

As in

A is cross-sectional area of the pipe [...]

I have seen both formulations, but mostly the first one. But I have to admit that my dictionary says the second one. I should follow my dictionary of course, but would like to confirm if the first one is useable or not.

The context is a technical physics report.


2 Answers 2


Cross-section (the noun) can be used attributively as an adjective (e.g. "airplane glue"), but since there's already an adjective in use, cross-sectional, using that existing adjective will sound better to many ears.


the area of a cross-section

a cross-sectional area


Cross-section is a noun. Cross-sectional is an adjective: it's the same as the noun with the adjectivalising "-al" on the end. So "cross-section area" isn't technically correct, while "cross-sectional area" is.

  • 1
    No. 'Cross-section area' should not be labelled 'isn't correct' or even 'isn't technically correct'; the use of nouns attributively is extremely productive. Should 'dogs home' (usually not apostrophised nowadays for the institutions) be 'canine home'? Although, as per Tim Romano's answer, many of us might prefer 'cross-sectional' here. Jun 7, 2015 at 19:50

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