cilium

(sĭlˈē-əm)

1. A microscopic hairlike process extending from the surface of a cell or unicellular organism. Capable of rhythmical motion, it acts in unison with other such structures to bring about the movement of the cell or of the surrounding medium.
2. An eyelash.
3. Botany One of the hairs along the margin or edge of a structure, such as a leaf, usually forming a fringe.