(swimming) a swimming pool, a pool / (billiards) pool, a game at billiards

pool, put together

needed, necessary

need, necessity

about, approximately

contract, promise / to contract, to shorten / approximately, roughly

water (sometimes cold and/or fresh) / drinking water / a fluid, liquid / a flood / (sumo) Short for 水入り (mizuiri): halting

an office pool: a betting pool conducted at one's place of employment

swimming pool

necessity (quality or state of being necessary, unavoidable, or absolutely requisite)