Definitions

1. noun

A short hair or bristle, especially one of the hairs on the margin of an eye, especially in certain invertebrates such as insects and arthropods.

“The insect’s compound eyes were surrounded by numerous cilia, which helped protect them.”

2. noun

A short hair or bristle, especially one of the hairs on the eyelids, especially in humans.

“The cilium on her upper eyelid was causing her irritation.”