"Cafeteria Catholicism" - the idea that Catholics can choose which church teachings they adhere to
The Camillians - kamilliaanid - камиллианцы (a Roman Catholic religious order named after St. Camillus de Lellis (1550-1614, born in Italy), patron saint of the sick. Members of the order wear a large red cross on their cassocks, a symbol which may have inspired Henri Dunant when he set up the International Red Cross)
Camouflage cassock - kamuflaaž rjassa - камуфляжная ряса (a vestment for Orthodox chaplains)
Canon - kaanon - канон (1. regulation concerning ecclesiastical life and behavior 2. ecclesiastical hymn 3. the daily rule of prayer, reading and so on)
The Cappadocian Fathers - Kapadookia isad - Отцы Каппадокии (Sts. Basil the Great, Gregory the Theologian and Gregory of Nyssa)
Carpocratians (from Carpocrates) - karpokradid - карпократы (an early Gnostic sect from the first half of the 2nd century from Alexandria, they believed that morality must be suspended and one must go through every possible sin of earthly life in order to leave this world)
St. Casimir Jagiellon (Polish: Kazimierz, Lithuanian: Kazimieras; October 3, 1458 – March 4, 1484) - a prince of the Kingdom of Poland and of the Grand Duchy of Lithuania. St. Casimir became a patron saint of Lithuania. In Vilnius, his feast day is marked annually with Kaziuko mugë (a trade fair) held on the Sunday nearest to March 4
Cathach - (the sixth-century Latin psalter of St Colum Cille (Columba), was acquired by Royal Irish Academy in 1843)
Cell (Greek kelli) - kellia - келлия (the room where a monastic lives)
Ceratonia - jaanileivapuu - кератония (believed to be an archaic remnant of a part of the Fabaceae family now generally considered to be extinct; in the Book of Enoch described as the tree of knowledge)
The chair for study of atheism - university of Miami starts in 2016 the nation’s first academic chair “for the study of atheism, humanism and secular ethics”
Chiliasm ("millennialism") - kiliasm - хилиазм (ancient heresy which teaches that Christ's Second Coming will be followed by a period of a thousand years during which Christ will rule on earth)
Christian social hostel - kiriku sotsiaalhotell - церковная социальная гостиница (temporary shelter for pregnant women in crisis. 73 such hostels at the beginning of 2020 in Russia)
Christa - a sculpture of Jesus as a nude woman. The 4-foot, 250-pound figure hung in New York’s Cathedral Church of St. John the Divine. Scandalous piece of art was created in 1975 by British artist Edwina Sandys
Codex Calixtinus - Kalikstuse koodeks - Кодекс Каликста (written in the mid-1100s under the auspices of Pope Calixtus II, tells us about the apostle St. James, whose remains are believed to have miraculously washed up on the coast of northwestern Spain, the Codex reported to be stolen from the cathedral's (Santiago de Compostela) archives on July 5, 2011)
Compline (Latin completorium - "complement") - the completion of all the Hours of the day in the Catholic church, the name was given by St. Benedict in the beginning of the sixth century
Compostela - a certificate of pilgrimage to Santiago di Compostela in Spain (one needs to walk a min of 100 km or cycle at least 200 km)
Concelebrator - one who serves the liturgy together with the main priest
Conversos - Jews converted to Christianity in 14th century Spain
Credencial ("pilgrim's passport") - a pass which is stamped with the official St. James stamp of each town at which the pilgrim has stayed (on his/her way to Santiago di Compostela)
Crypto-Christians - Christians, who practiced their faith secretly, so as to escape the persecution of the anti-Christian state
St. Coca - the 6th century Irish saint (traditionally a sister of St. Kevin of Glendalough), Kilcock (Cill Choca meaning "Coca's cell") town takes its name from her