“面积单位”和“单位面积”是不同的。首先，所谓面积单位，是指度量或计算物体表面或平面图形的大小时所采用的单位。如常用的公制面积单位有平方米、平方分米、平方厘米、平方毫米；常用的市制面积单位有平方丈、平方尺、平方寸。 “Area units” and “unit area” is different. First of all, the so-called area unit, refers to measure or calculate the size of the surface of the object or plane used by the unit. Such as the commonly used metric area units are square meters, square decimeters, square centimeters, square millimeters; commonly used municipal area units flat square feet, square feet, square inch.