Nictitating, a term used to describe the blinking or fluttering of the eyelids, has several synonyms. Some of the synonyms that convey similar meanings to nictitating are twinkling, winking, fluttering, and batting. While all these words have slight variations in their context of use, they all essentially signify the action of the eyelids closing and opening, often in rapid succession. Other synonyms that one may use in place of nictitating are flickering, flapping, and vibrating. These synonyms are commonly used in descriptions of insects or animals that have nictitating membranes, which are transparent eyelids that protect and moisten the eyes while allowing visibility.