wigwag

1. Any of a number of mechanical or electrical devices which cause a component to oscillate between two states.Examples: "I parked near a big sound stage building; lamped a red wig-wag signal rocking back and forth to indicate a scene being shot inside. This meant no admittance until the cameras had stopped grinding. Presently a bell jingled and the wig-wag died."; "WIG-WAG The red flashing light outside of a stage indicating that filming is going on."

2. Any of a number of mechanical or electrical devices which cause a component to oscillate between two states.Examples: "Rogan hit the wigwag flashers on the headlights of the Crown Vic and made it to the circular driveway at the Sixth Avenue entrance of the Hilton in four minutes flat."; "But it was equipped with a siren; blue lights concealed in the front grille; wig-wag, or blinking lights, in the rear; and a blue light on the front dashboard."; "[…] Claxton flipped on the flashing red and blue wigwag lights on his patrol car's front bumper. […] And the truck, apparently responding to the flashing wigwag lights, edged farther off the pavement onto the shoulder and stopped; properly, cooperatively, deceptively."

3. Any of a number of mechanical or electrical devices which cause a component to oscillate between two states.Examples: "Travelling home about half past ten o'clock on a recent night he had seen a motor-car which had been driven into the cattle-stop on the railway-line. It was a bad night from a visibility point of view, and the wig-wag was not operating, as no train was in sight. However, before the motor-car was extricated a train passed within three inches of it."; "The Seacliff train pulled out of Brighton station and gathered speed as it approached the level crossing with its wig-wag signal warning signal ringing out. Then the train's whistle blew deperately because, standing alone at the crossing, was a boy aged about three and a half. The little boy was I, was me, and I was engulfed by the noise and enthralled by the train's power."

4. Any of a number of mechanical or electrical devices which cause a component to oscillate between two states.Examples: "The wigwag is used for polishing the shoulders of pinions, pinion leaves, staffs and pivots, and for numerous other operations. […] These tools are used extensively in all the American watch factories."

5. Any of a number of mechanical or electrical devices which cause a component to oscillate between two states.Examples: "Some vehicles with air brakes also use a wigwag low pressure indicator. This is mounted above the windshield. If the air pressure drops below 60 psi, the signal arm will drop down across the windshield. You can't reset it (push it back out of view) until air pressure is brought above 60 psi. Don't operate the vehicle with the signal arm lever down."

6. Any of a number of mechanical or electrical devices which cause a component to oscillate between two states.Examples: "One of the first standard types of automated visual grade-crossing warning was the automated flagman, a signal commonly known as a "wigwag." According to Santa Fe documents, the wigwag was adopted as a standard crossing device by the American Railway Association in 1923. A standard wigwag is actuated by a track circuit and consists of a paddle with a red lamp that gracefully swings back and forth in a horizontal pattern when a train approaches. A wigwag is usually accompanied by a bell."US