CANONS: The word comes from the Latin canonicus. It originally designated the diocesan clergy, attached to a church under the jurisdiction of a bishop, as opposed to other priests serving private churches.
REGULAR: In the 11th century, after the Gregorian reform, some of the canons began living according to the Rule of Saint Augustine. They thus became Canons Regular.
OF THE LATERAN: In 1446, Pope Eugenius IV, to thank the Canons Regular for the invaluable services they rendered to the Basilica of St. John Lateran, granted them by decree the title of Canons Regular of the Lateran.