Adoration is generically, the act of worship (with profound reverence, says Webster).
Perpetual Adoration is the state of constant worship. Some sources refer to the process more formally as Perpetual Eucharistic Adoration. Perpetual Adoration appears to be a strictly Catholic tradition.
In the writings of the Benedictine Sisters of Perpetual Adoration and The Sisters of Saint Francis of Perpetual Adoration at least, it appears that this is taken somewhat figuratively with the assertion that they make their entire lives a process of adoration.1 & 2
The general understanding of Perpetual Adoration is constant worship implemented by some monasteries and convents. These organizations maintain a more formal and less personal stance on Perpetual Adoration as a community by keeping one or more members of the community in prayer at all times. Some of these organizations allow a break in adoration for mass that must use the chapel space.
The longest running uninterrupted prayer in the US began on 1 August 1878 by the Franciscan Sisters of Perpetual Adoration in La Crosse, Wisconsin, who have kept at least two of their members in adoration since they began. 3
Some of the practical concerns with Perpetual Adoration include: dedication of a separate chapel, an alter with Monstrance above a corporal, several candles beside the Monstrance, a telephone and a restroom in or near the chapel, code device locks that permit entry only to approved adorers, a schedule of adorers with phone numbers and backups, security light system for night time adorers, and convincing members that Perpetual Adoration is not too much responsibility. 4 & 5
The Holy Father Pope John Paul II has asked that every parish in the world have
perpetual adoration. On Dec. 12, 1981, the Pope himself began Perpetual Eucharistic
Adoration in a chapel at St. Peter's as an exhortation and encouragement for all parishes
to do the same. Yet the vast majority of parishes throughout the world do not have a
single hour of exposition and adoration of the Blessed Sacrament during the week. A
decree called "Papal Decree on Perpetual Eucharistic Adoration" was given on June 2,
1991 that makes it "emphatically clear that the church not only permits but wholeheartedly
encourages Perpetual Adoration of the Blessed Sacrament exposed for the faithful in
parishes." At the forty-fifth International Eucharistic Congress in June 1993 in Seville, Spain,
Pope John Paul II prayed that the fruit of the Congress be the establishment of Perpetual
Adoration in every parish throughout the world.