Syringa josikaea vs lilac

Syringa josikaea and lilac both are nouns.

Word	Noun	Adjective	Verb	Adverb
Syringa josikaea	Yes	No	No	No
lilac	Yes	Yes	No	No

As nouns, lilac is a hypernym of Syringa josikaea; that is, lilac is a word with a broader meaning than Syringa josikaea:

Syringa josikaea: central European upright shrub having elliptic leaves and upright clusters of lilac or deep violet flowers
lilac: any of various plants of the genus Syringa having large panicles of usually fragrant flowers

Syringa josikaea (noun)	lilac (noun)
central European upright shrub having elliptic leaves and upright clusters of lilac or deep violet flowers	any of various plants of the genus Syringa having large panicles of usually fragrant flowers

Syringa josikaea (adjective)	lilac (adjective)
	of a pale purple color