| C4 | fourth cervical nerve; fourth cervical vertebra; fourth component of complement |
|---|---|
| FF | degree of fineness of abrasive particles; fat-free; father factor; fecal frequency; fertility factor... |
| FC | fasciculus cuneatus; fast component [of a neuron]; febrile convulsions; feline conjunctivitis; ferri... |
| FTF | finger to finger |
| C4a | activated fourth component of complement |