源泉 (yuán quán): 분수.

For many writers, memories of childhood are the fountainhead of their creativity; those early experiences often turn into moving stories on the page.

Trust is the fountainhead of friendship; if friends are always suspicious of each other, even the deepest bond will gradually dry up.

Scientists believe that curiosity is the fountainhead that drives humanity to explore the unknown; without it, many major discoveries would be impossible.

That fertile land and abundant water are the fountainhead of the local farmers' livelihood for generations and the foundation of the whole village's prosperity.