burning bush vs Old Testament

burning bush and Old Testament both are nouns.

Word	Noun	Adjective	Verb	Adverb
burning bush	Yes	No	No	No
Old Testament	Yes	No	No	No

burning bush (noun)	Old Testament (noun)
(Old Testament) the bush that burned without being consumed and from which God spoke to Moses	the collection of books comprising the sacred scripture of the Hebrews and recording their history as the chosen people; the first half of the Christian Bible
densely branched Eurasian plant; foliage turns purple-red in autumn
deciduous shrub having purple capsules enclosing scarlet seeds
Eurasian perennial herb with white flowers that emit flammable vapor in hot weather