Another suggestion: Without seeing exactly what the document is referring to it is difficult to say, but it seems like they are talking about coupon testing as part of the test pyramid. This is generally carried out in order to satisfy a FAR or JAR requirement. FAR/JAR 25.1529 for example applies to GLARE. The testing order generally is coupon (material characteristics), element, detail, sub-component, component. Sort of a micro to macro approach to validate a design.

I have attached a couple of web links that explain more so you can see if it fits the context.

Hope it helps.

Test sections covers more potential fields than other terms, and sample is also sufficiently generic whilst being clear.