That which is exhibited to the eye; the appearance which anything manifests, especially any one among different and varying appearances of the same object.
- 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.
- Astronomy One of the cyclically recurring apparent forms of the moon or a planet.
- Physics A particular stage in a periodic process or phenomenon.
- Physics The fraction of a complete cycle elapsed as measured from a specified reference point and often expressed as an angle.
- Chemistry Any of the forms or states, solid, liquid, gas, or plasma, in which matter can exist, depending on temperature and pressure.
- Chemistry A discrete homogeneous part of a material system that is mechanically separable from the rest, as is ice from water.
- Biology A characteristic form, appearance, or stage of development that occurs in a cycle or that distinguishes some individuals of a group: the white color phase of a weasel; the swarming phase of locusts.
- To plan or carry out systematically by phases.
- To set or regulate so as to be synchronized.
- phase in To introduce, one stage at a time.
- phase out To bring or come to an end, one stage at a time.
- in phase In a correlated or synchronized way.
- out of phase In an unsynchronized or uncorrelated way.