sermon vs preaching

sermon and preaching both are nouns.

Word	Noun	Adjective	Verb	Adverb
sermon	Yes	No	No	No
preaching	Yes	No	No	No

As nouns, sermon and preaching are synonyms defined as:

sermon and preaching: an address of a religious nature (usually delivered during a church service)

Other synonyms of sermon include discourse.

As nouns, sermon and preaching are synonyms defined as:

sermon (noun)	preaching (noun)
an address of a religious nature (usually delivered during a church service)	an address of a religious nature (usually delivered during a church service)
a moralistic rebuke	a moralistic rebuke