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phase

(fāz)

1. A distinct stage of development: “The American occupation of Japan fell into three successive phases” (Edwin O. Reischauer).

2. A temporary manner, attitude, or pattern of behavior: just a passing phase.

3. An aspect; a part: We must reconsider every phase of the operation.

4. Astronomy

a. One of the cyclically recurring apparent shapes of the visibly illuminated portion of the moon or a planet.

b. The relative configuration, measured in angular units such as degrees or radians, of two orbiting bodies that periodically eclipse.

5. Physics

a. A particular stage in a periodic process or phenomenon.

b. The fraction of a complete cycle elapsed as measured from a specified reference point and often expressed as an angle.

6. Chemistry

a. Any of the forms or states, solid, liquid, gas, or plasma, in which matter can exist, depending on temperature and pressure.

b. A discrete homogeneous part of a material system that is mechanically separable from the rest, as is ice from water.

7. 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.

v. phased, phas·ing, phas·es

v. tr.

1. To plan or carry out systematically by phases.

2. To set or regulate so as to be synchronized.

v. intr.

To become incorporeal so as to be able to move through a solid object: “He got out of the car without opening the door—just phased through it—and walked up the steps of the church” (Dean Koontz).

Phrasal Verbs:

phase in

To introduce, one stage at a time.

phase out

To bring or come to an end, one stage at a time.

Idioms:

in phase

In a correlated or synchronized way.

out of phase

In an unsynchronized or uncorrelated way.

[Back-formation from New Latin phasēs, phases of the moon, from Greek phaseis, pl. of phasis, appearance, from phainein, to show; see bhā-¹ in the Appendix of Indo-European roots.]

phasic (fāzĭk) adj.

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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