late 14c., particuler, "a part or section of a whole, an individual circumstance, feature, or factor; an organ or part of the body," from particular (adj.). Meaning "a single instance or matter" is from 1530s; particulars "small details of statement" is from c. 1600.
"serving to explain; setting forth as an instance," 1620s, from Medieval Latin expositorius, from exposit-, past-participle stem of Latin exponere "set forth" (see expound). Earlier in English as a noun meaning "an expository treatise, commentary" (early 15c.). Related: Expositorial.
"precedent to be followed, illustrative instance; a pattern, model," c. 1300, variant of asaumple, from Old French essample "example" (see example). The survival of this variant form is due to its use in New Testament in KJV (1 Peter v.3). Tyndale (1526) there has insample.