waterhole

Meanings

1. A depression in which water collects, especially one where wild animals come to drink.
2. A watering hole; a place where people meet to drink and talk.
3. A part of the electromagnetic spectrum, between the regions where hydrogen and hydroxyl radiate, that is relatively quiet in terms of radio astronomy.

Etymology

* water + hole. * (astronomy): Coined by Bernard Oliver in 1971, in allusion to the idea that this part of the spectrum would be that used by extraterrestrial intelligence to communicate.