Placing “nano” before a measurement indicates “billionths” — that is there are billion per unit. For example, a nanometer is a billionth of a meter. A nanosecond is a billionth of a second. The prefix “nano” comes from the Latin nanus (“dwarf”).
But how big is a billionth? It’s really, really, really small. Here’s a visual for you: the width of single dime (or 1-yen coin) is about one billionth of the diameter of Earth. That is, you could line up a billion dimes from one side of the earth to the other (going through the middle of the planet).
Here’s another “billionth”: half the width of your little fingernail compared with the distance from New York to Los Angeles.
A computer takes just a few nanoseconds to carry out an instruction, such as adding two numbers. That means that in the time it takes you to blink your eye, a typical computer can do 900 million calculations.