A square rod is a unit of area measurement that is now considered obsolete and not commonly used in modern times. It was historically used in some English-speaking countries, including the United States and the United Kingdom, as part of the older system of land measurement.
One square rod is equal to an area of 1/160th of an acre or 1/4,840th of a square yard. In terms of square meters, one square rod is approximately equal to 25.29285264 square meters (m²).
The square rod was often used in land surveys and property descriptions in the past, but it has been largely replaced by more standardized systems of measurement. In modern times, square meters and square feet are the more commonly used units for measuring land area.
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.