Definition of phases:
(n) :
that which is exhibited to the eye; the
appearance which anything manifests, especially any one among different and varying appearances of the same object; any appearance or
aspect of an object of mental apprehension or view
"the problem has many phases."
(v) :
(to phase out) To discontinue (doing) something over a period of time (i.e., in phases); to stun or shock someone