FRANKPLEDGE
Etymology
From Anglo-Latin franciplegium, a Latinisation of Anglo-Norman frauncplege ("free pledge"), a mistranslation of Old English friĂ°borh ("pledge of peace") {which had the corrupted form friborh, which led to the Modern English term friborg}, as if it were *freoborh ("free pledge"). See also friborg, which refers to the predecessor of frankpledge.
Noun
frankpledge (plural frankpledges)
(law, historical) A form of collective suretyship and punishment under English law among the members of a tithing.
Any group so similarly answerable for the conduct of all its members and liable for collective punishment.
(law, historical) A decener: a member of a tithing bound in frankpledge.
(law, historical, uncommon) The tithing itself.
Source: Wiktionary
Frank"pledge`, n. Etym: [Frank free + pledge.] (O. Eng. Law)
(a) A pledge or surety for the good behavior of freemen, -- each
freeman who was a member of an ancient decennary, tithing, or
friborg, in England, being a pledge for the good conduct of the
others, for the preservation of the public peace; a free surety.
(b) The tithing itself. Bouvier.
The servants of the crown were not, as now, bound in frankpledge for
each other. Macaulay.
Source: Webster’s Unabridged Dictionary 1913 Edition