The radical sense is to throw, to shoot or dart, and it may be of the same family as clamo, clamor, a shoot of the voice.

A shoot of light; a beam; a ray; a small stream of light. A gleam of dawning light, metaphorically, a gleam of hope.

Brightness; splendor. In the clear azure gleam the flocks are seen.

To shoot or dart, as rays of light. At the dawn light gleams in the east.

To shine; to cast light.

To flash; to spread a flood of light.

Among falconers, to disgorge filth, as a hawk.