Textbook definition of Data augmentation
How about the definition from &quot;The Art of Data Augmentation&quot; by David A van Dyk &amp; Xiao-Li Meng:
The term data augmentation refers to methods for constructing iterative optimization or sampling algorithms via the introduction of unobserved data or latent variables.
Citation:
David A van Dyk &amp; Xiao-Li Meng (2001) The Art of Data Augmentation, Journal of Computational and Graphical Statistics, 10:1, 1-50, DOI: 10.1198/10618600152418584