Eructation - An act of belching.

Erythema - A redness of the skin.

Etiologic - Pertaining to the cause of disease.

Exotoxin - Soluble toxins, usually produced by gram-positive bacteria that have a specific toxic effect. These toxic substances are found outside the bacterial cell, or free in the culture medium.

Fasciculations - A small local contraction of muscles, visible through the skin, representing a spontaneous discharge of a number of fibers innervated by a single motor nerve filament.

FDA - Food and Drug Administration.

Fission - A nuclear process in which a heavier nucleus divides or spits into two or more lighter nuclei.

Flaccid - Weak, lax, and soft.

Flashblindness - A temporary visual interference effect that persists after the source of illumination has been removed. This is similar to the effect produced by flashbulbs, and can occur at exposure levels below those that cause eye damage.

Fluctuant - Showing varying levels.

Fomite - Objects that possibly harbor a disease agent and are capable of transmitting that disease (clothing, utensils).

Fulminant - Sudden, severe.

Fungi - Primitive plants which do not utilize photosynthesis and are capable of anaerobic growth. Most fungi form spores.

Fusion - Generally regarded as the opposite of fission. The joining of nuclei to form a heavier nucleus.