Sinhalese kūpa (3)
Clough’s Sinhala English Dictionary says Sinhalese word kúpa means “well, hole, hollow, mast, and tree or rock in the midst of a river.” It traces its origin to the Tamil root kappal through the transformation of kappal > kūpa > kūpa. The following words, related to Sinhalese kūpa, also originate from Tamil kappu.
kúpaka, “mast of a vessel; stake to which a boat is moored; leathern oil vessel; hollow below the loins; funeral pile.” kúpódaka, “well-water.”