nettle tree vs hackberry

nettle tree and hackberry both are nouns.

Word	Noun	Adjective	Verb	Adverb
nettle tree	Yes	No	No	No
hackberry	Yes	No	No	No

As nouns, nettle tree and hackberry are synonyms defined as:

nettle tree and hackberry: any of various trees of the genus Celtis having inconspicuous flowers and small berrylike fruits

nettle tree (noun)	hackberry (noun)
any of various trees of the genus Celtis having inconspicuous flowers and small berrylike fruits	small edible dark purple to black berry with large pits; southern United States
	any of various trees of the genus Celtis having inconspicuous flowers and small berrylike fruits