sermon vs lecture

sermon and lecture both are nouns.

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

As nouns, lecture is a hypernym of sermon; that is, lecture is a word with a broader meaning than sermon:

Other hypernyms of sermon include speech, talking to.

sermon (noun)	lecture (noun)
an address of a religious nature (usually delivered during a church service)	teaching by giving a discourse on some subject (typically to a class)
a moralistic rebuke	a speech that is open to the public
	a lengthy rebuke

sermon (verb)	lecture (verb)
	censure severely or angrily
	deliver a lecture or talk