Eire, Or Eyre

Eire, or eyre [fr. iter, Lat.], the Court of justices itinerant, justiciarii itinerantes, justices in eyre. They were anciently sent with a general commission into divers counties to hear such causes as are termed Pleas of the Crown; and this was done for the east of the people, who must else have been brought to the King's Bench, if the cause were too high for the County Court: it is said they were sent but once in seven years. the eyre of the forest is the justice-seat, which, by an ancient custom, was held every three years by the justices of the forest journeying up and down for that purpose, Bract. 1 3, c. xi.

A journey, route, circuit, Black's Law Dictionary, 7th Edn., p. 534