(D-glucose) is a sugar that's a stable, odorless, white crystalline powder or colorless crystal.
In its pure form, it has a dextrose equivalency (DE) of 100, which indicates that it's 100% pure Dextrose, not a mixture with other substances as well. Dextrose equivalency is a good value to know when purchasing Dextrose supplies.
Dextrose is commercially available in monohydrate or anhydrate form, termed Dextrose Monohydrate or Dextrose Anhydrate, respectively.
Monohydrate substances contain one water molecule, referred to as a molecule of water of hydration. These water molecules are said to be "coordinated" to the substance, which indicates a type of loose chemical linkage.
Dextrose Monohydrate is a sugar that contains one molecule of water per dextrose molecule, i.e. for every dextrose molecule, there is a water molecule loosely linked.
If a material is deemed anhydrate, it doesn't contain water. Dextrose is available in the anhydrate form as well, a.k.a. Dextrose Anhydrate; however, it's used mainly in the pharmaceutical industry.