A quinquennial visit ad limina, or simply an ad limina visit, is the required visit of Catholic residential diocesan bishops and certain prelates with territorial jurisdiction (such as territorial abbots) to the thresholds of the [tombs of the] Apostles Peter and Paul, and to meet the pope to report on the state of their dioceses or prelatures.
It is a formal trip usually made together by all bishops from a single region (viz., an episcopal conference) to discuss with the pope issues specific to their regions. It is separate from other trips a bishop might make to the Vatican, such as to attend a synod. The ad limina visit happens every five years, or quinquennially.
Limina is the accusative plural of the Latin noun limen, meaning literally "a threshold; the head-piece or foot-piece of a doorway," and in a transferred sense, "a house", "dwelling", or "abode." The Latin preposition ad means "to", "toward", or "at."
