| 1. | a person who heedlessly or maliciously reveals private or confidential matters; tattler; talebearer. |
| 2. | a thing serving to reveal or disclose something. |
| 3. | any of various indicating or registering devices, as a time clock. |
| 4. | Music. a gauge on an organ for indicating the air pressure. |
| 5. | an indicator showing the position of a ship's rudder. |
| 6. | a row of strips hung over a track to warn train crew members on freight trains that a low bridge, tunnel, or the like is approaching. |
| 7. | Yachting. (on a sailboat) a feather, string, or similar device, often attached to the port and starboard shrouds and to the backstay, to indicate the relative direction of the wind. |
| 8. | Squash. a narrow piece of metal across the front wall of a court, parallel to and extending 17 inches (43.2 cm) above the base: a ball striking this is an out. |
| 9. | that reveals or betrays what is not intended to be known: a telltale blush. |
| 10. | giving notice or warning of something, as a mechanical device. |