Old Testament vs Septuagint

Old Testament and Septuagint both are nouns.

Word	Noun	Adjective	Verb	Adverb
Old Testament	Yes	No	No	No
Septuagint	Yes	No	No	No

Old Testament (noun)	Septuagint (noun)
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	the oldest Greek version of the Old Testament; said to have been translated from the Hebrew by Jewish scholars at the request of Ptolemy II