A cubic centimetres (or cubic centimeters in US English) (SI unit symbol: cm; non-SI abbreviations: cc and ccm) is a commonly used unit of volume that extends the derived SI-unit cubic metre, and corresponds to the volume of a cube that measures 1 cm × 1 cm × 1 cm. One cubic centimetre corresponds to a volume of 1/1,000,000 of a cubic metre, or 1/1,000 of a litre, or one millilitre; thus, 1 cm ≡ 1 ml. The mass of one cubic centimetre of water at 3.98 °C (the temperature at which it attains its maximum density) is closely equal to one gram. Note that SI supports only the use of symbols and deprecates the use of any abbreviations for units. Hence cm is preferred to cc or ccm.