Ben Sira vs Ecclesiasticus

Ben Sira and Ecclesiasticus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ben Sira	Yes	No	No	No
Ecclesiasticus	Yes	No	No	No

As nouns, Ben Sira and Ecclesiasticus are synonyms defined as:

Ben Sira and Ecclesiasticus: an Apocryphal book mainly of maxims (resembling Proverbs in that respect)

Other synonyms of Ben Sira include Sirach, Wisdom of Jesus the Son of Sirach.

Ben Sira (noun)	Ecclesiasticus (noun)
an Apocryphal book mainly of maxims (resembling Proverbs in that respect)	an Apocryphal book mainly of maxims (resembling Proverbs in that respect)