"1 Cup" is equal to 8 fluid ounces in US Standard Volume. It is a measure often used in cooking.
A Metric Cup is slightly different: it is 250 milliliters (which is about 8.5 fluid ounces).
But there are also measuring cups, which are things used to measure liquids, or powders like flour or sugar.
As you fill up the measuring cup, you need to look at which number it is filled to.
Here we have 2/3 cup (two-thirds of a cup) of milk.
And they can also measure milliliters (ml):
Here we have 150 ml.
It doesn't say "150" ... it says "50" ... but it is half-way between 100 and 200 so you can figure out it is 150 ml.
There are also special ones designed to hold an exact amount, such as these 1/2 cup and 1/4 cup measures.
They can also hold more than "1 Cup" of liquid.
This measuring cup holds up to 4 cups of liquid. If the liquid goes all the way to the 3, then there are 3 cups of liquid. Between the numbers, you would find fractions of a cup.
2 cups of a liquid is the same thing as 1 pint. So this measuring cup also holds 2 pints (4 cups equals 2 pints).