Nanoparticles are isolated objects that are measured on the scale of nanometers, or billionths of a meter. All three dimensions of a nanoparticle need to be measurable on the nanoscale. Meanwhile, nanomaterials are materials made up of nanoparticles, and only one of their dimensions needs to be measurable on the nanoscale. As a result, nanoparticles are a category of nanomaterials.