Ecclesiasticus vs Sirach

Ecclesiasticus and Sirach both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ecclesiasticus	Yes	No	No	No
Sirach	Yes	No	No	No

As nouns, Ecclesiasticus and Sirach are synonyms defined as:

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

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

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