syntax

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The study of the rules whereby words or other elements of sentence structure are combined to form grammatical sentences.
• noun A publication, such as a book, that presents such rules.
• noun The pattern of formation of sentences or phrases in a language.
• noun Such a pattern in a particular sentence or discourse.
• noun Computers The rules governing the formation of statements in a programming language.
• noun A systematic, orderly arrangement.

from The Century Dictionary.

• noun Connected system or order; union of things.
• noun In grammar, the construction of sentences; the due forming and arrangement of words or members of sentences in their mutual relations according to established usage.

from the GNU version of the Collaborative International Dictionary of English.

• noun obsolete Connected system or order; union of things; a number of things jointed together; organism.
• noun That part of grammar which treats of the construction of sentences; the due arrangement of words in sentences in their necessary relations, according to established usage in any language.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A set of rules that govern how words are combined to form phrases and sentences.
• noun computing, countable The formal rules of formulating the statements of a computer language.
• noun linguistics The study of the structure of phrases, sentences and language.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the grammatical arrangement of words in sentences
• noun studies of the rules for forming admissible sentences
• noun a systematic orderly arrangement