Colour temperature (or correlated colour temperature, CCT) is a number indicating the degree of yellowness or blueness of a white light source. Measured in kelvins (K), CCT represents the temperature an incandescent object (like a filament) must reach to mimic the colour of the lamp.
Yellowish-white (warm) sources, like incandescent lamps, have lower colour temperatures in the 2700K-3000K range; white and bluish-white (cool) sources have higher colour temperatures. Basically the higher the colour temperature, the whiter/bluer the light will be.
Like photography, room lighting requires an accurate selection of light sources to ensure that it meets the functional and aesthetic requirements of the space. Lighting schemes created for different types of rooms will need to feature different colour tones, depending on the specific function that they serve (video conferencing rooms, work spaces, showcase areas, reception areas etc.).
Have a close look at the colour temperature when selecting the light source for your room or check with your lighting designer before you buy it.
To see how colour temperature affects your lighting environment, just have a look here.