zdiac.html - {n.} 1. The exact time when an attack or other military action is supposed to start. * /Zero hour for the bombers to take off was midnight./ 2. The time when an important decision or change is supposed to come; the time for a dangerous action. * /It was zero hour and the doctor began the operation on the man./ * /On the day of the championship game, as the zero hour came near, the players grew nervous./

zdiac.html - {v.} 1. To adjust a gun so that it will exactly hit (a target); aim at. * /Big guns were zeroed in on the enemy fort./ * /American missiles have been zeroed in on certain targets, to be fired if necessary./ 2. {slang} To give your full attention to. * /The Senate zeroed in on the Latin-American problems./ * /Let's zero in on grammar tonight./

zdiac.html - {v. phr.}, {slang} To stop talking; keep a secret; shut your mouth; be quiet. * /The man was getting loud and insulting and the cop told him to button his lip./ * /John wanted to talk, but Dan told him to keep his lip buttoned./ Syn.: KEEP ONE'S MOUTH SHUT, SHUT UP.

zdiac.html - See: BUTTON ONE'S LIP.

zdiac.html - {n.} A defense in a sport (as basketball or football) in which each player has to defend a certain area. * /The coach taught his team a zone defense because he thought his players weren't fast enough to defend against individual opponents./

zdiac.html - {v. phr.}, {slang} 1. To fall asleep very quickly. * /Can I talk to Joe? - Call back tomorrow, he zonked out./ 2. To pass out from fatigue, or alcohol. * /You won't get a coherent word out of Joe, he has zonked out./