The "square" rating (e.g., "2.5-square wire") refers to a nominal value defined by national standards; users select the appropriate wire size based on the electrical load requirements.
"Wire square" is a colloquial term used during electrical installation and renovation; the figure cited (e.g., "2.5") implies the unit of square millimeters.
The "square" rating actually indicates the wire's cross-sectional area-specifically, the area of its circular cross-section-measured in square millimeters.
