A fimbria (plural fimbriae) is a Latin word that literally means "fringe." It is commonly used in science and medicine, with its meaning depending on the field of study or the context. For example:

• In bacteriology, fimbria is a proteinaceous appendage in many gram-negative bacteria that is thinner and shorter than a flagellum. This appendage ranges from 3-10 nanometers in diameter and can be up to several micrometers long. Fimbriae are used by bacteria to adhere to one another during mating and to adhere to animal cells. A bacterium can have as many as 1,000 fimbriae. Fimbriae are only visible with the use of an electron microscope.

• With regard to the brain, fimbria is a prominent band of white matter along the medial edge of the hippocampus. The fimbria is an accumulation of myelinated axons (mostly efferent) that first collect on the ventricular surface of the hippocampus as the alveus (a thin layer resembling an inverted trough). Near the splenium the fimbria separates from the hippocampus as the crus of the fornix.

• In the female reproductive system, the fimbria is a fringe of tissue near the ovary leading to the Fallopian tube. When ovulation is about to occur, the sex hormones activate the fimbria, causing it to hit the ovary in a gentle, sweeping motion.

• Cognomen of Roman general Gaius Flavius Fimbria (d. 84 BC).

Fimbria | Fimbrie | 菌毛