lesson vs significance

lesson and significance both are nouns.

Word	Noun	Adjective	Verb	Adverb
lesson	Yes	No	No	No
significance	Yes	No	No	No

As nouns, significance is a hypernym of lesson; that is, significance is a word with a broader meaning than lesson:

Other hypernyms of lesson include import, meaning, signification.

lesson (noun)	significance (noun)
a task assigned for individual study	the quality of being significant
a unit of instruction	a meaning that is not expressly stated but can be inferred
punishment intended as a warning to others	the message that is intended or expressed or signified
the significance of a story or event