Look up correlated color temperature
on Wikipedia and then look at the color temperature sliders in ACR or Lightroom (ACR shown below). The top slider (blue-yellow) moves the color temperature along the Planckian locus, which describes color emitted by a black body radiator.
however, the OP is also right that the Kelvin scale in ACR/LR is inverse
compared to the colors and Kelvin marks along the Planckian locus in the CIE xy chromaticity diagram.
Bruce Fraser wrote:
>> The Temperature slider indicates, in kelvins, the color of the light for which Camera Raw is trying to compensate. Moving the slider toward higher color temperatures (bluer light) results in a warmer, yellower image, while moving toward lower color temperatures (yellower light) results in a colder, bluer image. You can think of the Temperature slider as a blue-to-yellow control. The Tint slider controls the axis that runs perpendicular to color temperature, so it’s essentially a green-magenta control — negative values add green, positive ones add magenta. <<