The totality of features and characteristics of a product or service that bear on its ability to satisfy stated or implied needs of the customer.
By Prof. J M Juran :
"Fitness for use". Prof.. Juran says that fitness is defined by the customer. Expanded version is Fitness for Use, Purpose, Reliability, Value for Money & Conformance to the defined Requirements
By Prof. Noriaki Kano:
Defines quality as a two - dimensional model, which has two dimensions: 1) "must - be quality" and 2) "attractive quality". The second dimension is more close to the "fitness for use" stated by Prof. Juran. While the second dimension is the one customer would love to have, but he has not given a thought to it yet.
By Dr. Genichi Taguchi:
The definition of quality as given by Dr. Taguchi is based on a more comprehensive view of the product creation system. Here the Quality is related to (or, to be more precise, to the lack of quality) "The loss a product would impose on the society after its shipment".
Definition By Software Engineering Perspective: