Quality in everyday language, business, engineering and manufacturing has a pragmatic interpretation as the non-inferiority, superiority or usefulness of something. This is the most common interpretation of the term. ~ Wikipedia

http://www.thefreedictionary.com/quality

qual·i·ty(kwl-t)

n. pl. qual·i·ties

1.

a. An inherent or distinguishing characteristic; a property.

b. A personal trait, especially a character trait: “The most vital quality a soldier can possess is self-confidence” George S. Patton.

2. Essential character; nature: “The quality of mercy is not strain’d” Shakespeare.

3.

a. Superiority of kind: an intellect of unquestioned quality.

b. Degree or grade of excellence: yard goods of low quality.

4.

a. High social position.

b. Those in a high social position.

5. Music Timbre, as determined by harmonics: a voice with a distinctive metallic quality.

6. Linguistics The character of a vowel sound determined by the size and shape of the oral cavity and the amount of resonance with which the sound is produced.

7. Logic The positive or negative character of a proposition.

adj.

Having a high degree of excellence: the importance of quality health care. ~ Free Online Dictionary

http://en.wikipedia.org/wiki/Quality

The meaning for the term quality has developed over time. Various interpretations are given below:

ISO 9000 – “Degree to which a set of inherent characteristic fulfills requirements”

(Philip B. Crosby in the 1980s)- “Conformance to requirements”. The difficulty with this is that the requirements may not fully represent what the customer wants; Crosby treats this as a separate problem.

(Joseph M. Juran).- “Fitness for use”. Fitness is defined by the customer.

(Noriaki Kano and others)- A two-dimensional model of quality. The quality has two dimensions: “must-be quality” and “attractive quality”. The former is near to the “fitness for use” and the latter is what the customer would love, but has not yet thought about. Supporters characterize this model more succinctly as: “Products and services that meet or exceed customers’ expectations”. One writer believes (without citation) that this is today the most used interpretation for the term quality.

(Gerald M. Weinberg)- “Value to some person”.

(W. Edwards Deming)- “Quality and the Required Style of Management” 1988 See http://www.deming.org/. “Costs go down and productivity goes up, as improvement of quality is accomplished by better management of design, engineering, testing and by improvement of processes. Better quality at lower price has a chance to capture a market. Cutting costs without improvement of quality is futile.”

(Genichi Taguchi). “The loss a product imposes on society after it is shipped”. Taguchi’s definition of quality is based on a more comprehensive view of the production system.

Energy quality, associated with both the energy engineering of industrial systems and the qualitative differences in the trophic levels of an ecosystem.

One key distinction to make is there are two common applications of the term Quality as form of activity or function within a business. One is Quality Assurance which is the “prevention of defects”, such as the deployment of a Quality Management System and preventative activities like FMEA. The other is Quality Control which is the “detection of defects”, most commonly associated with testing which takes place within a Quality Management System typically referred to as Verification and Validation.