phase: • A distinct stage of development: "The American occupation of Japan fell into three successive phases" (Edwin O. Reischauer).
• A temporary manner, attitude, or pattern of behavior: just a passing phase.
• An aspect; a part: every phase of the operation.
stage: • A level, degree, or period of time in the course of a process: the toddler stage of child development; the early stages of a disease.
• A point in the course of an action or series of events: too early to predict a winner at this stage.