| 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. |