Software Quality
Quality may be defined as the totality of features and characteristics of a software product that relate to its ability to satisfy stated or implied needs
Software quality characteristics are the attributes of a software product by which its quality is described and evaluated
[ISO/IEC IS 9126 91], [ISO/IEC WD 9126-1 94]
A software quality metric specifies a quantitative scale and method which can be used to determine the value of the feature.
A quality model refers to a specific set of software quality characteristics.