The colour temperature refers to the colour produced by a light. It's measured in Kelvin (K) and ranges from warm white (1700K - 3000K) to daylight white (6500K). Neutral white (3100K - 5000K) is mainly used for general lighting applications.
The colour code is a combination of the colour rendering index (CRI) and the colour temperature (K). The first number refers to the CRI (1 = very poor colour rendering, 9 = maximum accuracy). The second and third numbers refer to the colour temperature. For example, a light with a colour code of 830 has very good colour rendering and produces a warm white light.