wellhead

Etymology

From well + head.

noun

1. The place where a spring breaks out of the ground; the source of water for a stream or well.
   Leaue the troubled streames, 1607, George Chapman, Bussy D'Ambois, London: William Aspley, act I, scene 1, page 3
   It is a singular circumstance, that within a quarter of a mile of the well-head of the Wye, arises the Severn. 1789, William Gilpin, Observations on the River Wye, London: R. Blamire, Section 6, p. 74
2. (figurative) The source of something; a fountainhead.
   … a bull was not merely a stud animal worth so much, due to go to the butcher in a little while. It was a vast wonder-beast, a well-head of the great, furnace-like passion that makes the worlds roll and the sun surge up … 1932, D. H. Lawrence, “Painted Tombs of Tarquinia”, in Etruscan Places, New York: Viking, published 1957, page 113
3. The surface structure of an oil well etc.