''Ordo'' (Latin "order, rank, class") may refer to: * A musical phrase constructed from one or more statements of a

rhythmic mode In medieval music, the rhythmic modes were set patterns of long and short duration (music), durations (or rhythms). The value of each musical notation, note is not determined by the form of the written note (as is the case with more recent Europea ...

pattern and ending in a rest *

Big O notation Big ''O'' notation is a mathematical notation that describes the asymptotic analysis, limiting behavior of a function (mathematics), function when the Argument of a function, argument tends towards a particular value or infinity. Big O is a memb ...

in calculation of algorithm computational complexity * Orda (organization), also ''ordo'' or ''horde'', was a nomadic palace for the Mongol aristocrats and the Turkic rulers *

Order (biology) Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognize ...

, in the taxonomy of organisms * Ordo Recitandi or directorium gives complete details of the celebration of the Eucharist and the Liturgy of the Hours, beginning with the first Sunday of Advent * Religious order in

monasticism Monasticism (; ), also called monachism or monkhood, is a religion, religious way of life in which one renounces world (theology), worldly pursuits to devote oneself fully to spiritual activities. Monastic life plays an important role in many Chr ...

* The Inquisition from '' Warhammer 40,000'' has three main ordines: Ordo Malleus, Ordo Hereticus and Ordo Xenos * Ordo Templi Orientis, an organization dedicated to the religious philosophy of Thelema * The scholarly economic/political science journal ''The ORDO Yearbook of Economic and Social Order'' * Canderous Ordo, a fictional character in the Star Wars video games '' Star Wars: Knights of the Old Republic'' and '' Star Wars Knights of the Old Republic II: The Sith Lords'' * A fictional encryption program from the book ''

Cryptonomicon ''Cryptonomicon'' is a 1999 novel by American author Neal Stephenson, set in two different time periods. One group of characters are World War II–era Allied codebreakers and tactical-deception operatives affiliated with the British Govern ...

'', by Neal Stephenson * Novus ordo seclorum which appears on the reverse of the Great Seal of the United States * Ordo Missae or Order of Mass, the order (regulation) of the Eucharist in the Roman Rite of the

Catholic Church The Catholic Church (), also known as the Roman Catholic Church, is the List of Christian denominations by number of members, largest Christian church, with 1.27 to 1.41 billion baptized Catholics Catholic Church by country, worldwid ...

* Ordo (military unit), a Roman military unit, originally a maniple, at the Imperial times, the centuria

See also