The word "nano" comes from the Greek word meaning "dwarf". The prefix "nano" (abbreviated: n) has been defined in science as a billionth fraction of a unit. So there are values of the order 10^-9. The unit itself is usually SI-compliant.

The two most abundant units in this form are in electrical engineering the nano-farad [nF] to indicate the capacitance of a capacitor and the nano-meter [nm] as a length or size specification at the atomic level, both in mathematics, physics and chemistry.

Nevertheless, the size of nano-particles is difficult to imagine. In this physical limit where the transition of classical physics to quantum physics is done, the laws of Max Planck have already been described in the early 20th century – the bulk properties of a material step back towards the surface properties.

All the more surprising, however, the effects achievable in everyday life. Here nanotechnology comes into play. It deals with the technical implementation of scientific findings. The generated nano-materials are already omnipresent in nano-products for consumers, such as suntan lotion, car tires, plaster or paint.

Here atoms and molecules (a group of at least two atoms) are selectively rearranged and grouped to achieve the desired properties. In practice, various possibilities of this change in the properties have emerged depending on the application.

In addition to the approach based on polymers (for example: silicones), the approach based on mineral oxides has been proven. They are, for example, silicon dioxide, zirconium oxide and titanium oxide, which are used in various proportions according to their use and are dissolved in water or ethanol (alcohol). The substances identified are all found in nature and are well known. The best example is the use of sand (quartz) as a starting material for each type of mineral glass.

Nano-objects are classified according to the international standard ISO / TS 27687. They have to measure at least into one dimension (length, width or height) between one and one hundred nanometers. Very small nano-objects are called quantum dots and consist only of a few atoms or molecules.
The origin of nanomaterials can help in classification. There may be natural nano-objects that arise as fine dust particles in dust storms or volcanic eruptions. Humans also unintentionally produce daily nanoparticles, like soot in exhaust gases, cigarette smoke, grinding dust, while welding or blasting. The last group are the nanomaterials industrially synthetically produced. Their number and thus occurrence in the environment, however, is many times smaller than that of the natural nano-objects.

The three basic forms of nano-objects are the following:

• Nanoparticles measure in all three dimensions between one and one hundred nanometers
• Nanotubes or nanorods (also called nanofibers) are in two dimensions between 1...100 nm
• Nanoplates and nanolayers (including surface coatings) have only one dimension between one and one hundred nanometers, usually referred to as layer thickness