Sonification: A Definition

The term 'Sonification' is quite abstract and not really known to a broad majority, even including most auto-correct software :-) It is often misunderstood or used in the wrong context. To get a clear understanding what sonification is and (even more important) what it is not, several definitions and articles talking about sonification in general have been studied. 
First of all, the not scientific but quite commonly used and beloved source Wikipedia describes sonification as "the use of non-speech audio to convey information or perceptualize data", referencing to one of the most famous books in the field by Gregory Kramer: "Auditory Display: Sonification, Audification, and Auditory Interfaces". This definition is fairly similar to the actual definition of Auditory Display itself, which basically is transporting information through sound.
The paper by Thomas Herrmann "Taxonomy and Definition for Sonification and Auditory Display" goes deeper into the term's meaning and tries to define 'Sonification' in more detail:

"A technique that uses data input, and generates sound signals (eventually in response to additional excitation or triggering) may be called sonification, if and only if

• The Sound reflects objective properties or relations in the input data
• The transformation is systematic. This means that there is a precise definition provided of how the data (and optional interactions) cause the sound to change
• The sonification is reproducible: given the same data and identical interactions (or triggers) the resulting sound has to be structurally identical
• The system can intentionally be used with different data, and also used in repetition with the same data."

This clearly underlines the mathematical aspect of sonification, stressing the fact the the term describes a scientific method and is indeed not an artisitc approach towards data:

"Being a scientific method, a prefix like in 'scientific sonification' is not necessary. Same as some data visualizations my be 'viewed' as art, sonifications may be heard as 'music', yet this use differs from the original intent."

This is a definite statements and clearly separates data sonification from many musical projects working with scientific data. Though the line between artistic music projects and actual data sonification projects might be a bit blurry. The difference a visual piece of art related to or created from scientific data and an actual visual graph the clearly represents numbers is similar to the difference between music and sonification and makes it easier to differentiate:

"This automatically distinguishes signification from music, where the purpose is not in the precise perception of what interactions are done with an instrument or what data caused the sound, but on an underlying artistic level that operates on a different level."

So though both, music and sonification belong to the family of 'organized sounds', they have different purposes and functions which clearly separates them from each other. This actually excludes musical data projects mentioned in a previous post from data sonification.

It is highly important to keep those definitions and differences in mind when creating and designing the sounds and interactions for a sonification project, as the danger to drift off into a more musical and artisticc approach, rather than a scientific sonification project during the creative process is quite high and has to be recognized rather sooner than later.

References 

KRAMER, G. (1994). Auditory display: sonification, audification, and auditory interfaces. Reading, Mass, Addison-Wesley.

Hermann, T. (2008) Taxonomy and Definitions for Sonification and Auditory Display. Paris: International Conference for Auditory Display.