A phase's one part or portion in recurring or serial activities or occurrences logically connected within a greater process, often resulting in an output or a change. Phase or phases may also refer to: In science and engineering Phase problem, the loss of information (the phase) from a physical measurement Phase (matter), a physically distinctive form of a substance, such as the solid, liquid, and gaseous states of ordinary matter Phase transition's the transformation of a thermodynamic syste… (More on Phases)