The definition of a colloid (any colloid)contains the size of the material dispersed which is between 1 nanometer to 1000. Nano Technology would define the particle range as being 100 nanometers or smaller. However, any Colloidal Silver (and yes, there is such a thing as colloidal ions, and ions can be molecules, larger than a single atom) is generally 90% Nano tech particle size.
I prefer to make my own Colloidal Silver (90% Colloidal Electrolyte aka silver ions, and 10% metallic silver). Your body absorbs the silver ions with the help of metallothionein (a metalloprotein) in your saliva which protects the ions from the chlorides formed in the stomach and the chlorides in the blood. Metallothionein actively transports silver to the cells; so silver chloride formation is a non-issue.
Metallic Silver has to be absorbed passively (no biological system to transport it)over the intestines, and by osmosis over the cellular walls. Both work, both are colloids, but bottle Colloidal Silver is too expensive.