Different terms for the same concepts. You could call it high- and low-level requirements, customer/supplier requirements or requirements and specification. While the form is important, a common understanding is core to be able to work together.
As okl said, it’s arguably terminology, and maybe high and low level requirements would work for you? I prefer to separate out the terms though, so that “requirements” are the thing that the engineering team can’t unilaterally change without upsetting the stakeholders. If I can change a spec item mid-delivery and it doesn’t matter to the customer, then it wasn’t a requirement. If I can’t change it, then it’s a requirement.