I have not seen this type of testing in software testing.
The references I know of refer to where companies do testing to identify customer leads for a product it appears to be based on Taguchi analysis.
One definition I found - cannot find who to attribute this to is:
Another of my passions is multivariate testing of conceptual content. Such content is evaluated according to some favorite criterion. If it is art, one might rate it on one dimension ("I like it", to "yuck!"), or it might be rated on various dimensions (naturalness, emotion-evokingness, viscerality, etc). Other applications include advertising, instructional material, speech writing, etc.
One problem with multivariate testing of conceptual content is that interaction effects cannot be contained as readily as they can when using multivariate split testing to optimize physical mechanisms or processes. Thus, one cannot reach statistical confidence as soon as one might wish, or one must learn to live with uncertainty more than otherwise.
<font size="2" face="Verdana, Arial, Helvetica">In what context did you hear this term as relates to software testing?
I will add that this answer is based on my experience which is certainly not definitive.