cilium

/ˈsɪl.i.əm/noun
Middle School
1

A short microscopic hairlike organelle projecting from a eukaryotic cell (such as a unicellular organism or one cell of a multicelled organism) which serve either for propulsion by causing currents in the surrounding fluid or as sensors.

2

One of the fine hairs along an insect's wing.

3

One of the hairs or similar protrusions along the margin of an organ.

4

An eyelash.