| de forest | (n) United States electrical engineer who in 1907 patented the first triode vacuum tube, which made it possible to detect and amplify radio waves (1873-1961), Syn. Lee De Forest, Father of Radio |
| prevent | (v) keep from happening or arising; make impossible, Syn. preclude, forestall, forbid, foreclose, Example: My sense of tact forbids an honest answer; Your role in the projects precludes your involvement in the competitive project |