instrument

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

• noun A tool or implement used to do or facilitate work, especially a small precision tool used by a professional.
• noun A device for recording, measuring, or controlling, especially such a device functioning as part of a control system.
• noun Music A device for playing or producing music.
• noun A means by which something is done; an agency.
• noun One used by another to accomplish a purpose; a dupe.
• noun A legal document, especially one that represents a right of payment or conveys an interest, such as a check, promissory note, deed, or will.
• transitive verb To provide or equip with instruments.
• transitive verb Music To compose or arrange for performance.

from The Century Dictionary.

• noun Something that serves as a means to the effecting of an end; anything that contributes to the production of an effect or the accomplishment of a purpose; a means; an agency.
• noun Specifically Something used to produce a mechanical effect; a contrivance with which to perform mechanical work of any kind; a tool, implement, utensil, or machine.
• noun Specifically In music, a mechanical contrivance or apparatus for producing musical sounds—that is, for setting up, either in a solid body or in a confined body of air, vibrations sufficiently rapid, regular, and definite to produce tones systematically related to one another.
• noun One who is used by another; a human tool.
• noun In law, a writing given as the means of creating, securing, modifying, or terminating a right, or affording evidence, as a writing containing the terms of a contract, a deed of conveyance, a grant, a patent, an indenture, etc.
• noun See the adjectives. Synonyms Implement, Utensil, etc. See tool.
• In music, to compose or arrange for instruments, especially for an orchestra; score.

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

• noun That by means of which any work is performed, or result is effected; a tool; a utensil; an implement; a device
• noun A contrivance or implement, by which musical sounds are produced.
• noun (Law) A writing, as the means of giving formal expression to some act; a writing expressive of some act, contract, process, as a deed, contract, writ, etc.
• noun One who, or that which, is made a means, or is caused to serve a purpose; a medium, means, or agent.
• transitive verb To perform upon an instrument; to prepare for an instrument.
• transitive verb To furnish or equip with instruments; to attach instruments to.

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

• noun A device used to produce music.
• noun A measuring or displaying device.
• noun A tool, implement used for manipulation or measurement
• noun law A legal document, such as a contract, deed, trust, mortgage, power, indenture, or will.
• noun figuratively A person used as a mere tool for achieving a goal.
• verb transitive To apply measuring devices.
• verb transitive To devise, conceive, cook up, plan.
• verb To perform upon an instrument; to prepare for an instrument.

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

• verb write an instrumental score for
• verb address a legal document to
• noun the semantic role of the entity (usually inanimate) that the agent uses to perform an action or start a process
• noun the means whereby some act is accomplished
• noun a person used by another to gain an end
• noun (law) a document that states some contractual relationship or grants some right
• verb equip with instruments for measuring, recording, or controlling
• noun any of various devices or contrivances that can be used to produce musical tones or sounds
• noun a device that requires skill for proper use