Phase, aspect, side, facet, angle are comparable when they denote one of the possible ways in which an object of contemplation may be seen or may be presented.
Phase may distinctly imply a change in the appearance of a thing without a change in the observer's point of view. From its original denotation as one of the four different shapes which the moon apparently assumes during its waxing and waning it often suggests a cyclical change in appearance.
In extended use it is often applied to an outward and passing manifestation of a stage in growth, development, or unfolding, but it also may apply to one of two or more distinctive appearances or values of something with little or no suggestion of cyclical or temporal succession.
Aspect sometimes implies a change in appearance without a shifting in point of view, but unlike phase it usually suggests a superficial change, especially one brought about by unpredictable circumstances.
More distinctively it implies a change in appearance that is traceable to a change in the observer's point of view. Thus, one who proposes to treat the phases of the depression of the nineteen-thirties implies that he intends to consider its stages as they manifested themselves outwardly; one who proposes to treat all aspects of that depression implies that he intends to consider it from every possible point of view (as the political, the economic, and the sociological).
Side, though often used interchangeably with phase and aspect, may retain implications derived from other of its senses and is used chiefly in reference to something that may be thought of as having two or more faces and therefore not fully apprehensible unless it or its observer shifts position.
But side differs from phase and aspect in less regularly connoting appearance or referring to physical or intellectual vision.
Facet differs from side in implying a multiplicity of other faces similar to or like the one singled out for attention.
Angle denotes an aspect which is observable from a point of view restricted in its scope.