1. 
[syn: wellhead, wellspring]
2.  a structure built over a well; 
The Collaborative International Dictionary of English v.0.48:
Wellhead \Well"head`\, n.
   A source, spring, or fountain.
   [1913 Webster]
         At the wellhead the purest streams arise. --Spenser.
   [1913 Webster]
         Our public-school and university life is a great
         wellhead of new and irresponsible words. --Earle.
   [1913 Webster]
WordNet (r) 3.0 (2006):
wellhead
    n 1: the source of water for a well [syn: wellhead,
         wellspring]
    2: a structure built over a well