Key

1. a small metal instrument specially cut to fit into a lock and move its bolt. 2. any of various devices resembling or functioning as a key: the key of a clock. 3. key card. 4. something that affords a means of access: the key to happiness. 5. something that secures or controls entrance to a place: Gibraltar is the key to the Mediterranean. 6. something that affords a means of clarifying a problem. 7. a book, pamphlet, or other text containing the solutions or translations of material given elsewhere, as testing exercises. 8. a systematic explanation of abbreviations, symbols, etc., used in a dictionary, map, etc.: pronunciation key. Compare legend (def 4). 9. the system, method, pattern, etc., used to decode or decipher a cryptogram, as a code book, machine setting, or keyword. 10. one of a set of marked parts, designated areas, or levers pressed in operating a typewriter, computer terminal, calculator, etc. 11. a manually operated lever for opening and closing an electric circuit, used to produce signals in telegraphy. 12. Music. (in a keyboard instrument) one of the levers that when depressed by the performer sets in motion the playing mechanism. (on a woodwind instrument) a metal lever that opens and closes a vent. the relationship perceived between all tones in a given unit of music and a single tone or a keynote; tonality. the principal tonality of a composition: a symphony in the key of C minor. the keynote or tonic of a scale. 13. tone or pitch, as of voice: to speak in a high key. 14. mood or characteristic style, as of expression or thought: He writes in a melancholy key. 15. degree of intensity, as of feeling or action. 16. a pin, bolt, wedge, or other piece inserted in a hole or space to lock or hold parts of a mechanism or structure together; a cotter. 17. a small piece of steel fitting into matching slots of a hub of a wheel or the like and the shaft on which the wheel is mounted so that torque is transmitted from one to the other. 18. a contrivance for grasping and turning a bolt, nut, etc. 19. Computers. a field or group of characters within a record that identifies the record, establishing its position among sorted records, and/or provides information about its contents. 20. (in a series of advertisements or announcements soliciting replies) a unique code inserted for each medium used, to determine the relative effectiveness of the media. 21. Electricity. a device for opening and closing electrical contacts. a hand-operated switching device ordinarily formed of concealed spring contacts with an exposed handle or push button, capable of switching one or more parts of a circuit. 22. Biology. a systematic tabular classification of the significant characteristics of the members of a group of organisms to facilitate identification and comparison. 23. Masonry. a keystone. 24. Architecture. (in a ribbed vault) a stone, as a boss, at the intersection of two or more ribs. 25. Masonry, Carpentry. a wedge, as for tightening a joint or splitting a stone or timber. 26. Carpentry. a small piece of wood set into a timber across the grain to prevent warping. 27. Building Trades. any grooving or roughness applied to a surface to improve its bond with another surface. 28. Basketball. keyhole (def 2). 29. Photography. the dominant tonal value of a picture, a high-key picture having light tonal values and minimal contrast and a low-key picture being generally dark with minimal contrast. 30. Painting. the tonal value and intensity of a color or range of colors: Rembrandt's colors are characterized by their low key. 31. Botany. a samara. 32. (initial capital letter) a member of the House of Keys. 33. keys, spiritual authority.