The Fechnerian theory of perception is based on the idea that the intensity of a sensation is proportional to the logarithm of the stimulus intensity.

She completed the task feckfully.

The fechavirus is a newly discovered virus that affects cats.

Fechaviruses are a group of viruses that infect plants.

She looked purr-fect in her new dress.

Fecal microbiota transplants have been shown to be effective in treating certain gastrointestinal conditions.