What is segmentation?
According to the computer vision community, a segmentation is a disjoint partition of an image into K regions. Popular segmentation strategies include (but are not limited to): normalized cuts, graph cuts, mean-shift, watershed. Researches sometimes use the outputs of these 'segmentation engines' in the middle of their own algorithm. However, according to Jitendra Malik (paraphrased from CVPR 2006) segmentation is the result of recognition and not that disjoint partition that is returned by your favorite 'segmentation engine'.
Perhaps Jitendra would prefer to call these 'segmentation engines' something else such as 'hypothetical perceptual grouping' engine. I would have to agree with Jitendra that segmentation is what we want at the end of recognition.