currajong vs bottle tree

currajong and bottle tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
currajong	Yes	No	No	No
bottle tree	Yes	No	No	No

As nouns, bottle tree is a hypernym of currajong; that is, bottle tree is a word with a broader meaning than currajong:

currajong: widely distributed tree of eastern Australia yielding a tough durable fiber and soft light attractively grained wood; foliage is an important emergency food for cattle
bottle tree: an Australian tree of the genus Brachychiton

Other hypernyms of currajong include bottle-tree.

currajong (noun)	bottle tree (noun)
widely distributed tree of eastern Australia yielding a tough durable fiber and soft light attractively grained wood; foliage is an important emergency food for cattle	an Australian tree of the genus Brachychiton