Definition of pool:
a small and rather deep collection of (usually) fresh water, as one supplied by a spring, or occurring in the course of a stream; a reservoir for water; as, the pools of Solomon. --Wyclif; a small body of standing or stagnant water; a puddle
"charity will hardly water the ground where it must first fill a pool. --Francis Bacon."
put together; contribute to a common fund, on the basis of a mutual division of profits or losses; to make a common interest of; as, the companies pooled their traffic; combine or contribute with others, as for a commercial,speculative
, or gambling transaction
"finally, it favors the pooling of all issues. -- Grant."