The 2018 Farm Bill defines hemp as Cannabis sativa L. with a delta-9 THC concentration of not more than 0.3 percent on a dry-weight basis.
That sentence is federal. States can be stricter, and they change their minds. A product can fail the hemp definition after harvest, after processing, or because a lab measured a different THC number than the one the statute names. This lesson is orientation, not legal advice for a business.
Legal hemp is a number plus a statute, not a feeling. Check the state you are standing in.