零度 literally means 'zero degrees' and is most commonly used for temperature, especially zero degrees Celsius (the freezing point of water). It can also appear in other measurement scales such as longitude (zero degrees meridian). Unlike the standalone number 零 (zero), 零度 always refers to the specific point on a scale—temperature, angle, or other graduated measures. In everyday Chinese, 零度 usually implies 摄氏零度 (Celsius zero) unless another scale is specified.