|an extraordinary or unusual thing, person, or event; an exceptional example or instance.|
|a chattering or flighty, light-headed person.|
|chemotaxis (kē'mō-tāk'sĭs, kěm'ō-) Pronunciation Key
The characteristic movement or orientation of an organism or cell along a chemical concentration gradient either toward or away from the chemical stimulus. Bacteria exhibit chemotaxis when they move toward a source of nutrients.