|≈||approximately equal to|
|digits||indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …)|
The acre-foot is a unit of volume commonly used in the United States in reference to large-scale water resources, such as reservoirs, aqueducts, canals, sewer flow capacity, irrigation water, and river flows.
The drop is an approximated unit of measure of volume, the amount dispensed as one drop from a dropper or drip chamber. It is often used in giving quantities of liquid drugs to patients, and occasionally in cooking.