in an electric utility system. a single primary line affixed to a pole or cross arm. Technically. phase refers to the synchronized movement of electrical energy and pertains to common designs of electric supply lines such as single phase (one primary conductor). two phase (two primary conductors). or three phase (three primary conductors).
Merriam-Webster Online Dictionary
phase (noun)1.
a particular appearance or state in a regularly recurring cycle of changes - phases of the moon
2.
a) a distinguishable part in a course, development, or cycle - the early phases of her career
b) an aspect or part (as of a problem) under consideration
3.
the point or stage in a period of uniform circular motion, harmonic motion, or the periodic changes of any magnitude varying according to a simple harmonic law to which the rotation, oscillation, or variation has advanced from its standard position or assumed instant of starting
4.
a homogeneous, physically distinct, and mechanically separable portion of matter present in a nonhomogeneous physicochemical system
5.
an individual or subgroup distinguishably different in appearance or behavior from the norm of the group to which it belongs , also the distinguishing peculiarity
transitive verb
1.
to adjust so as to be in a synchronized condition
2.
to conduct or carry out by planned - phases
3.
to introduce in stages - usually used with in phase in new models
phase (Wikipedia)