What is Software quality?

Which word are you unclear on?  Software?  or quality?

An oxymoron!

In the context of software engineering, software quality refers to two related but distinct notions that exist wherever quality is defined in a business context:

• Software functional quality reflects how well it complies with or conforms to a given design, based on functional or specifications. That attribute can also be described as the fitness for purpose of a piece of software or how it compares to competitors in the marketplace as a worthwhile product
• Software structural quality refers to how it meets non-functional requirements that support the delivery of the functional requirements, such as robustness or maintainability, the degree to which the software was produced correctly.

In the context of software engineering,

Software quality measurement is about quantifying to what extent a software or system possesses desirable characteristics. This can be performed through qualitative or quantitative means or a mix of both. In both cases, for each desirable characteristic, there are a set of measurable attributes the existence of which in a piece of software or system tend to be correlated and associated to this characteristic. For example, an attribute associated with portability is the number of target-dependent statements in a program.