A libation is a ritual pouring of a drink as an offering to a god. It was common in the religions of antiquity, including Judaism:
"And Jacob set up a Pillar in the place where he had spoken with him, a Pillar of Stone; and he poured out a drink offering on it, and poured oil on it". (Genesis 35:14)
The liquid used in libations varied; most commonly it was wine or olive oil. The vesssel., such a patera, used in the ritual often had a significant form which differentiated it from secular vessels. The liquid was poured onto something of religious signficance, very often the ground itself, as an offering to the Earth.

Hero of Alexandria in his Pneumatica described a mechanism for automating the process, by using altar fires to force oil from the cups of two statues.