In raising the question of form-bearing dimension in music, we are trying to understand the possibilities and limits of the apprehension musical form in terms of the psychological mechanisms that operate on a received acoustic structure. To approach this understanding theoretically and experimentally, we need to define the notion of form-bearing dimension and to develop some ideas on the interactions that take place between perceptual processes and memory structures as form is accumulated in the mind of a listener. Three areas of psychological concern are discussed: perceptual grouping processes, abstract musical knowledge structures and event structure processing. For each area, the constraints on different musical dimensions such as pitch, duration, dynamics and timbre are examined in light of their potential to carry musical form. ((Keywords)) : auditory grouping, event structure, form-bearing dimension, knowledge structure, mental representation, musical form, perceptual invariance, psychological constraints.