A milliliter (sometimes written as millilitre) is a measurement of volume that is equal to one thousandth of a liter, meaning that it takes one thousand milliliters to equal one liter. A liter is a measurement of the amount of space that a liquid takes up in a container, which is equal to 1.056688 quarts. To understand this better, picture a gallon of milk. It takes 4 quarts of milk to make up one gallon of milk. Since one liter is a little bit more than one quart, 4 liters of milk is a little bit more than one gallon of milk. Now that you know how much is in a liter, you can tell that a milliliter is a very small amount of liquid. The measurements stated above are based on those used in the United States. Milliliters are often used in healthcare to measure amounts on liquid medicine.
There are about 5 (4.92) milliliters in one teaspoon and 29.57 milliliters to make one fluid ounce. Milliliter is often abbreviated as mL or as 1cm3. Milliliter comes from the Greek word "milli" meaning "one thousand," and the Greek word "litra" meaning "pound." Put the two words together and you have "one thousand(th) (of a) pound."