Home stereo eq is designed to work on a stereo mix, plain and simple. It's usually set so that the pivot point on the treble and bass controls is at the center of the audio range, i.e., 1,000 Hz (equal number of octaves above and below this frequency). Typical stereo tone controls are simple shelving devices designed to raise or lower everything equally.
Pro audio equalizers are more surgical in nature, designed to sculpt the sound in a pleasing way by boosting or cutting various user selected frequencies and offering a broader range of sculpting tools. They're usually quieter, lower distortion, and less obtrusive then their home stereo cousins.
They are also more likely to be used on an individual instrument track, rather than the whole stereo mix, however there are mastering eqs which are super precise (and VERY expensive).