Petit definitions

Webster's 1828 Dictionary

PETIT, a. pet'ty. Small; little; mean.
This word petit is now generally written petty.
Petit constable, an inferior civil officer subordinate to the high constable.
Petit jury, a jury of twelve freeholders who are empanneled to try causes at the bar of a court; so called in distinction from the grand jury, which tries the truth of indictments.
Petit larceny, the stealing of goods of the value of twelve pence, or under that amount; opposed to grand larceny.
serjeanty, in English law, the tenure of lands of the king, by the service of rendering to him annually some implement of war, as a bow, an arrow, a sword, lance, etc.
Petit treason, the crime of killing a person, to whom the offender owes duty or subjection. Thus it is petit treason for a wife to kill her husband, or a servant his lord or master.

Merriam Webster's

adjective Etymology: Middle English, small, minor, from Anglo-French, small Date: 14th century petty 1 — used chiefly in legal compounds

Oxford Reference Dictionary

adj. esp. Law petty; small; of lesser importance. Phrases and idioms: petit jury = petty jury. Etymology: ME f. OF, = small, f. Rmc, perh. imit. of child's speech

Webster's 1913 Dictionary

Petit Pet"it, a. [F. See Petty.] Small; little; insignificant; mean; -- Same as Petty. [Obs., except in legal language.] By what small, petit hints does the mind catch hold of and recover a vanishing notion. --South. Petit constable, an inferior civil officer, subordinate to the high constable. Petit jury, a jury of twelve men, impaneled to try causes at the bar of a court; -- so called in distinction from the grand jury. Petit larceny, the stealing of goods of, or under, a certain specified small value; -- opposed to grand larceny. The distinction is abolished in England. Petit ma[^i]tre. [F., lit., little master.] A fop; a coxcomb; a ladies' man. --Goldsmith. Petit serjeanty (Eng. Law), the tenure of lands of the crown, by the service of rendering annually some implement of war, as a bow, an arrow, a sword, a flag, etc. Petit treason, formerly, in England, the crime of killing a person to whom the offender owed duty or subjection, as one's husband, master, mistress, etc. The crime is now not distinguished from murder.