order (n.)

c. 1200, "body of persons living under a religious discipline," from Old French ordre "position, estate; rule, regulation; religious order" (11c.), from earlier ordene, from Latin ordinem (nominative ordo) "row, line, rank; series, pattern, arrangement, routine," originally "a row of threads in a loom," from Proto-Italic *ordn- "row, order" (source also of ordiri "to begin to weave;" compare primordial), which is of uncertain origin. Watkins suggests it is a variant of PIE root *ar- "to fit together," and De Vaan finds this "semantically attractive."

The original English word reflects a medieval notion: "a system of parts subject to certain uniform, established ranks or proportions," and was used of everything from architecture to angels. Old English expressed many of the same ideas with endebyrdnes. From the notion of "formal disposition or array, methodical or harmonious arrangement" comes the meaning "fit or consistent collocation of parts" (late 14c.).

Meaning "a rank in the (secular) community" is first recorded c. 1300. Sense of "a regular sequence or succession" is from late 14c. The meaning "command, directive" is first recorded 1540s, from the notion of "that which keep things in order." Military and honorary orders grew out of the fraternities of Crusader knights.

The business and commerce sense of "a written direction to pay money or deliver property" is attested by 1837; as "a request for food or drink in a restaurant" from 1836. In natural history, as a classification of living things next below class and next above family, it is recorded from 1760. Meaning "condition of a community which is under the rule of law" is from late 15c.

In order "in proper sequence or arrangement" is from c. 1400; out of order "not in proper sequence or orderly arrangement" is from 1540s; since 20c. principally mechanical, but not originally so ("and so home, and there find my wife mightily out of order, and reproaching of Mrs. Pierce and Knipp as wenches, and I know not what," - Pepys, diary, Aug. 6, 1666).

Phrase in order to "for the purpose of" (1650s) preserves etymological notion of "sequence." In short order "without delay" is from 1834, American English; order of battle "arrangement and disposition of an army or fleet for the purposes of engagement" is from 1769. The scientific/mathematical order of magnitude is attested from 1723.

order (v.)

c. 1200, ordren, "give order to, to arrange in a row or rank," from order (n.). Sense of "set or keep in order" is from c. 1500. Meaning "to give commands for or to, instruct authoritatively" is from 1540s; that of "command to be made, done, or issued" is from 1763. Related: Ordered; ordering.

Definitions of order
order (n.)
(often plural) a command given by a superior (e.g., a military or law enforcement officer) that must be obeyed;
the British ships dropped anchor and waited for orders from London
order (n.)
a degree in a continuum of size or quantity;
it was on the order of a mile
an explosion of a low order of magnitude
Synonyms: order of magnitude
order (n.)
established customary state (especially of society);
order ruled in the streets
law and order
order (n.)
logical or comprehensible arrangement of separate elements;
we shall consider these questions in the inverse order of their presentation
Synonyms: ordering / ordination
order (n.)
a condition of regular or proper arrangement;
the machine is now in working order
he put his desk in order
Synonyms: orderliness
order (n.)
a legally binding command or decision entered on the court record (as if issued by a court or judge);
a friend in New Mexico said that the order caused no trouble out there
Synonyms: decree / edict / fiat / rescript
order (n.)
a commercial document used to request someone to supply something in return for payment and providing specifications and quantities;
IBM received an order for a hundred computers
Synonyms: purchase order
order (n.)
a formal association of people with similar interests;
men from the fraternal order will staff the soup kitchen today
Synonyms: club / social club / society / guild / gild / lodge
order (n.)
a body of rules followed by an assembly;
Synonyms: rules of order / parliamentary law / parliamentary procedure
order (n.)
a group of person living under a religious rule;
the order of Saint Benedict
Synonyms: monastic order
order (n.)
(biology) taxonomic group containing one or more families;
order (n.)
a request for something to be made, supplied, or served;
I gave the waiter my order
the company's products were in such demand that they got more orders than their call center could handle
order (n.)
(architecture) one of original three styles of Greek architecture distinguished by the type of column and entablature used or a style developed from the original three by the Romans;
order (n.)
the act of putting things in a sequential arrangement;
there were mistakes in the ordering of items on the list
Synonyms: ordering
order (v.)
give instructions to or direct somebody to do something with authority;
She ordered him to do the shopping
Synonyms: tell / enjoin / say
order (v.)
make a request for something;
order a work stoppage
order (v.)
issue commands or orders for;
Synonyms: prescribe / dictate
order (v.)
bring into conformity with rules or principles or usage; impose regulations;
Synonyms: regulate / regularize / regularise / govern /
order (v.)
bring order to or into;
order (v.)
place in a certain order;
order the photos chronologically
order (v.)
appoint to a clerical posts;
Synonyms: ordain / consecrate / ordinate
order (v.)
arrange thoughts, ideas, temporal events;
Synonyms: arrange / set up / put
order (v.)
assign a rank or rating to;
Synonyms: rate / rank / range / grade / place
Order (n.)
(usually plural) the status or rank or office of a Christian clergyman in an ecclesiastical hierarchy;
Synonyms: Holy Order