What does phase mean?
A phase is a distinct stage in the development of a process, a period marked by particular conditions, or a stage in a repeating cycle. The word is especially useful when a larger undertaking must be understood as unfolding in stages: a project may enter its final phase, a career may pass through several phases, or the moon may show a particular phase. As a verb, phase means to arrange, introduce, or retire something gradually in stages, as when a company phases in a new system. The term often suggests an orderly progression rather than a sudden transition, although it can also refer to a temporary or difficult period. Across technical fields, phase describes recurring stages or synchronized states, but in ordinary conversation it chiefly conveys the idea of progression through recognizable stages.
A distinct stage or period in a process, development, or recurring cycle.
"The first phase of the project focused on research and planning."
Widely used in general, scientific, technical, and organizational contexts.
To organize, introduce, or carry out something in separate stages.
"The city will phase in the new parking restrictions over six months."
Often used with in, out, over, or through: phase in, phase out, and phase over.
The plural is phases, as in the early phases of development.
"The project passed through several phases before reaching completion."
The word phase comes from a Greek word meaning “appearance,” reminding us that every process reveals itself in stages.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does phase come from?
The word comes through French from the Greek phasis, meaning “an appearance” or “a phase of the moon,” from phainein, “to appear.” Ancient Greek astronomers used the term for the changing appearances of the moon. Its modern sense of a distinct stage developed from the idea of something becoming visible or taking form in successive stages.
Related word forms
How phase is actually used
In general use, phase suggests a formally defined or recognizable stage. In physics and engineering, it has more technical meanings, including the position of an oscillating system and the relationship between electrical circuits. The verb phase is common in organizational, technological, and policy contexts.
Easily confused with phase
A phase is a stage in a process, whereas to faze someone is to shock or unsettle them.