What does the "C" mean in "Mater. Sci. Eng. C" ISO4 standard naming for the &quot;Material Science&quot; field is as follows:

Mater. Sci. Eng. C
Material Science &amp; Engineering: C

What does the C mean?
The ISO code does not refer to the field, but to a journal. The C is not an abbreviation; rather there are 4 journals with this name, each with a different focus, indexed A, B, C, and R.

A focuses on Structural Materials: Properties, Microstructure and Processing
B focuses on Advanced Functional Solid-State Materials
C focuses on Materials for Biological Applications
R is for review articles

Such a nomenclature is generally used when a journal's scope has become too broad and it needs to be split into multiple journals. Physical Review uses a similar system, for example.