a discernible part or stage in a course, development, or cycle

an aspect or part, e.g. of a problem, under consideration

a particular appearance or state in a regularly recurring cycle of changes

the phases of the moon

in physics, a particular stage of progress reached in a regularly recurring motion or cyclic process with respect to a standard or reference position or assumed starting point; the point to which a rotation, oscillation, or periodic variation has advanced, considered in its relation to a standard or starting position

a homogeneous, physically distinct, and mechanically separable portion of matter present in a complex mixture the constituents of which have different physical states

a cyclically recurring or geographical variation in the appearance, e.g. coat or plumage colours, of an animal or bird

(usu in passive) to conduct or carry out (a project, etc) by planned phases

(also + with) to schedule (operations, etc) or contract for (goods or services) to be performed or supplied as required

to adjust (something) so as to be in phase with something else