To put it very simply: quality = how good something is. But not "good" like a person can be good or bad, but "good" like "made well."

Quality: –noun 1. an essential or distinctive characteristic, property, or attribute: the chemical qualities of alcohol. 2. character or nature, as belonging to or distinguishing a thing: the quality of a sound. 3. character with respect to fineness, or grade of excellence: food of poor quality; silks of fine quality. 4. high grade; superiority; excellence: wood grain of quality. 5. a personality or character trait: kindness is one of her many good qualities. 6. native excellence or superiority. 7. an accomplishment or attainment. 8. good or high social position: a man of quality. 9. the superiority or distinction associated with high social position. 10. Acoustics . the texture of a tone, dependent on its overtone content, that distinguishes it from others of the same pitch and loudness. 11. Phonetics . the tonal color, or timbre, that characterizes a particular vowel sound. 12. Logic . the character of a proposition as affirmative or negative. 13. Thermodynamics . the proportion or percentage of vapor in a mixture of liquid and vapor, as wet steam. 14. social status or position. 15. a person of high social position: He's quality, that one is. –adjective 16. of or having superior quality: quality paper. 17. producing or providing products or services of high quality or merit: a quality publisher. 18. of or occupying high social status: a quality family. 19. marked by a concentrated expenditure of involvement, concern, or commitment: Counselors are urging that working parents try to spend more quality time with their children.

Quality 1. General: Measure of excellence or state of being free from defects, deficiencies, and significant variations. ISO 8402-1986 standard defines quality as "the totality of features and characteristics of a product or service that bears its ability to satisfy stated or implied needs." 2. Manufacturing: Strict and consistent adherence to measurable and verifiable standards to achieve uniformity of output that satisfies specific customer or user requirements. 3. Objective: Measurable and verifiable aspect of a thing or phenomenon, expressed in numbers or quantities, such as lightness or heaviness, thickness or thinness, softness or hardness. 4. Subjective: Attribute, characteristic, or property of a thing or phenomenon that can be observed and interpreted, and may be approximated (quantified) but cannot be measured, such as beauty, feel, flavor, taste. http://www.businessdictionary.com/definition/quality.html http://www.qualitydigest.com/html/qualitydef.html