petty jury vs petit jury

petty jury and petit jury both are nouns.

Word	Noun	Adjective	Verb	Adverb
petty jury	Yes	No	No	No
petit jury	Yes	No	No	No

As nouns, petty jury and petit jury are synonyms defined as:

petty jury and petit jury: a jury of 12 to determine the facts and decide the issue in civil or criminal proceedings

petty jury (noun)	petit jury (noun)
a jury of 12 to determine the facts and decide the issue in civil or criminal proceedings	a jury of 12 to determine the facts and decide the issue in civil or criminal proceedings