Keening

The keening screech of the brakes startled the pedestrians on the sidewalk.

As the fog rolled in, a keening foghorn warned ships of the treacherous rocks ahead.

The keening of the steam whistle signaled the departure of the train from the platform.

The traveler explored foreign lands with a keening spirit, constantly seeking new experiences.

The old television emitted a high-pitched keening noise whenever it was turned on.