'Phase out' definitions:

Definition of 'phase out'

From: WordNet
verb
Terminate gradually [ant: phase in]

Definition of 'Phase out'

From: GCIDE
  • Phase out \Phase" out`\ (f[=a]z" out`), v. t. To halt (an activity) in steps, or gradually; as, to phase out use of 386-based PC's. [PJC]