What does monophase mean?
Monophase describes an electrical system, circuit, machine, or supply that uses one phase of alternating current. In this context, “phase” refers to the position of a sinusoidal waveform within its repeating cycle, not to a stage in a project or process. A monophase arrangement is contrasted with multiphase and three-phase systems, which combine multiple alternating waveforms and are commonly used for heavier industrial equipment. The adjective is much more common than the noun. Although “single-phase” may sound more readily understandable, monophase is established in technical literature, particularly in descriptions of motors, generators, transformers, and power distribution. The word is mainly encountered in electrical engineering and related technical documentation rather than everyday conversation.
Consisting of, operating from, or involving a single phase of alternating current.
"The motor is designed to run on a monophase supply."
Chiefly used in electrical engineering and technical specifications.
A single-phase electrical system, supply, or signal.
"The device requires a stable monophase to operate correctly."
This noun is uncommon; “single-phase system” or “single-phase supply” is often clearer.
Rare; the plural is used chiefly in specialized technical writing.
"The technician compared the two monophases before replacing the controller."
One phase, one wave: monophase is electrical language for power that follows a single alternating-current cycle.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does monophase come from?
Monophase combines the Greek-derived combining form mono-, meaning “one” or “alone,” with phase, a word ultimately derived from Greek phasis, meaning “appearance.” The expression developed in electrical vocabulary to distinguish systems using one alternating-current phase from those using several. Its first element is cognate with English words such as monogram, monopoly, and monophonic, all of which reflect Greek monos, “single” or “alone.”
How monophase is actually used
This is chiefly technical electrical vocabulary. It is most often used in specifications, installation guides, and engineering documentation; the noun form is comparatively uncommon.
Easily confused with monophase
Monophase describes an electrical system with one alternating-current phase, whereas monophonic describes music or sound consisting of a single melodic line.
Monophasic and monophase have closely related technical meanings, but monophasic specifically characterizes something as being in one phase.