introduce vs phase in

introduce and phase in both are verbs.

Word	Noun	Adjective	Verb	Adverb
introduce	No	No	Yes	No
phase in	No	No	Yes	No

As verbs, phase in is a hyponym of introduce; that is, phase in is a word with a more specific, narrower meaning than introduce:

Other hyponyms of introduce include open up, pioneer, debut.

introduce (verb)	phase in (verb)
be a precursor of	introduce gradually
place, fit, or thrust (something) into another thing
put before (a body)
cause to come to know personally
furnish with a preface or introduction
bring before the public for the first time, as of an actor, song, etc.
put or introduce into something
bring something new to an environment
bring in or establish in a new place or environment
bring in a new person or object into a familiar environment