As I understand it, abstraction is the term we use for when more meaning is created out of something simpler without altering it. It is derived from the latin verb abstrahere (to ‘draw away’). For instance, text is just one abstraction of binary data—as are bitmaps. So, in computers, text and bitmaps exist on top of (are implemented in terms of) binary data.

My question is: what is the opposite term? If I want to know the possible more basic things that bitmaps could be implemented in terms of other than binary data—things like tiles for a mosaic or fabric patches for a patchwork quilt—what am I asking for? Is there a word for that?

Abstraction has connotations of generalization and the opposite process of that is specialization. IDK whether that helps.