A square nanometer (often abbreviated as nm²) is a unit of area in the International System of Units (SI) and is used to describe extremely small areas, especially in the context of nanotechnology and scientific research.
One square nanometer is equal to one billionth of a square meter (1 x 10^-9 m²). In other words, it takes one billion square nanometers to make up one square meter.
To give you a sense of scale, a square nanometer is incredibly tiny. It's often used to describe the size of individual atoms, molecules, or the features on nanoscale devices. Nanotechnology deals with structures and materials on this extremely small scale, where traditional units of area, like square meters or even square millimeters, are impractical.
The "square foot (US survey)" is a unit of area used in the United States primarily for land surveying and mapping purposes. It differs from the standard square foot because it is based on the U.S. survey foot, which is a historical unit of length used in land surveying in the United States. The U.S. survey foot is slightly different from the international foot.
One square foot (US survey) is equal to approximately 0.0929034119223 square meters (m²) or about 0.111111 square yards (yd²).
This unit is used in various land-related applications, particularly in the United States, where the U.S. survey foot and the square foot (US survey) are still employed for legal and historical reasons in certain land surveys and property descriptions. It's essential to be aware of the specific units being used when dealing with land measurements to avoid any discrepancies or errors.