noun, plural: pili
(microbiology) Short, filamentous projection on a bacterial cell, used not for motility but for adhering to other bacterial cell (especially for mating) or to animal cells.
Bacterial pili are involved in cell adhesion. Specialized structures (called sex pili) have an important role in conjugation with another bacterial cell. The major constituent of a pilus is a protein called pilin.
Word origin: a combining form meaning “hair,”
- fimbria (microbiology)