Definition of grades

This whole grade thing is quite confusing. I was looking at another site that sells Lugol's and found the following:


DEFINITION OF GRADES

* Reagent ACS -- Meets or surpasses latest American Chemical Society standards for purity.
* Reagent -- Does not exceed maximum limits of significant impurities as stated. Does not have ultrastringent requirements of Reagent ACS.
* Laboratory Grade -- Equivalent in purity to United States Pharmacopeia (USP) and National Formulary (NF) listings. However, they are not offered for food, drug, or medicinal use of any kind.
* Practical Grade -- Sufficiently high quality for use in many syntheses and other applications.
* Technical Grade -- Selected commercial grades, scrupulously clean, and of reasonable chemical purity. Where usable, most economical grade and suitable for educational purposes