order Rhamnales vs plant order

order Rhamnales and plant order both are nouns.

Word	Noun	Adjective	Verb	Adverb
order Rhamnales	Yes	No	No	No
plant order	Yes	No	No	No

As nouns, plant order is a hypernym of order Rhamnales; that is, plant order is a word with a broader meaning than order Rhamnales:

order Rhamnales: an order of dicotyledonous plants, containing the families Elaeagnaceae, Leeaceae, Rhamnaceae, and Vitaceae (Rhamnales)
plant order: the order of plants

order Rhamnales (noun)	plant order (noun)
an order of dicotyledonous plants, containing the families Elaeagnaceae, Leeaceae, Rhamnaceae, and Vitaceae (Rhamnales)	the order of plants