| an extraordinary or unusual thing, person, or event; an exceptional example or instance. |
| a screen or mat covered with a dark material for shielding a camera lens from excess light or glare. |
| Cockcroft (kŏk'krôft') Pronunciation Key
British physicist who, with Ernest Walton, was the first to successfully split an atom using a particle accelerator in 1932. For this work they shared the 1951 Nobel Prize for physics. |