Order Order Majel Barrett Order (from Latin ordo "row, rank, series, arrangement", Old French ordre from the Latin accusative, ordinem, attested in English from the 1220s). The word conveys a notion of "a system of parts subject to certain uniform, established ranks or proportions", an idea very central to scholastic thought, and it was used in a wide range of contexts, from architecture to angels.

The monastic orders, originating with Anthony the Great and Benedict of Nursia from ca. 300 (see also Holy Orders)
- based on these, the military orders of the crusades
- based on these in turn, the various chivalric orders established since the 14th century.
- from these, the purely honorary decorative orders
In the sense of Command, in legal and military contexts:
- Court order
- Executive order
- General order
- Standing order
- Direct order
in the sense of "sequence, hierarchy" in scientific classification
- Order (biology)
- Social order
- Order of reaction
- In mathematics:
  - In a sequence, one item comes first, another second, another third, etc.; these ordinal numbers specify the order in which the items appear. Hence the next meaning of this word:
  - Order of an ordered set; see also Order theory, Total order, Total preorder and partial order
  - Order of a group or its elements. See Order (group theory).
    - Order of an element in some modulus, see Multiplicative order
  - Order of a Differential equation
  - Order of a root of a Polynomial
  - Big O notation (mathematical), aka the order of an Algorithm
  - Orders of magnitude are factors of ten
- in computer science:
  - Canonical order
  - Order (schema) The number of defining symbols in a Schema.
Miscellaneous meanings
- In Information processing, order is a measure of the number of objects or sub-systems in a System as seen by an Observer.
- Collating order
- Order (philosophy)
- Order (business)
- Architectonic orders: see Classical order
- Ordered sets of pitches or pitch classes such as a Tone row, see the mathematical meaning above.

"The Order"
- The Order (AKA Bruders Schweigen or Silent Brotherhood) was an American revolutionary National Socialist group.
- The Order is the title of a 2001 and a 2003 Film.

See also