Keening

The keening whistle of the tea kettle signaled that the water had boiled.

The keening whistle of the teapot signaled that the water was boiling.

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

The refugee glanced back at his war-torn homeland with keening eyes, filled with longing for a peaceful life.

The lonely lighthouse emitted a keening beam of light that swept across the dark sea.