What is c.f. meaning?

As an AI language model, I am not sure which specific meaning of 'c.f.' you are referring to, as it could have different meanings in different contexts. Here are some possible meanings of c.f.:

1. "Compare with" or "in comparison with": common abbreviation used in academic writing to indicate a comparison or contrast with something else. For example, "The results of our study show a significant difference in the treatment group c.f. the control group."

2. "Carried forward": abbreviation used in financial accounting to indicate the transfer of an unused balance or loss from one fiscal period to the next.

3. "Confer": abbreviation used in academic writing to suggest reading a certain source for more information or clarification. For example, "For a more detailed explanation of this concept, c.f. Smith (2015)."

4. "Coefficient of friction": a metric used in physics to describe the amount of friction between two surfaces.

5. "Cystic fibrosis": a genetic disorder that affects the lungs, digestive system, and other organs, leading to a buildup of thick mucus.

These are just a few examples of the different possible meanings of c.f. depending on the context.