headspring(n = noun.location) fountainhead, head - the source of water from which a stream arises; "they tracked him back toward the head of the stream"
is a kind of beginning, origin, root, rootage, source

   Fountain; source. [1913 Webster]
"The headspring of our belief." [1913 Webster]

headspring, n.
1 the main source of a stream.
2 a principal source of ideas etc.