Your camera probably has a mechanical shutter.
There are metal curtains that travel across the frame.
It may have an electronic shutter.
The sensor turns on and off.
Shutter speeds are usually fractions of a second.
On most cameras, both the numerator and denominators are shown, such as 1/250.
On older cameras, only the numerator is shown, such as 250.
Shutter speeds that are full seconds are denoted by a quote mark or the abbreviation sec.
2" is a two-second exposure, for example.
Because we're familiar with fractions, the shutter speed numbers are more understandable than lens opening numbers.
However, we can use the same mnemonic sentence to understand the different shutter speeds.
The bigger the number, the less light reaches the sensor.
You can set the shutter by using the shutter-priority exposure mode.
In this exposure mode, you change the shutter speed, and the camera selects the aperture.
On Nikon cameras, and many others, this mode is called S.
On Canon cameras, the mode is called Tv.
If you're using the shutter-priority exposure mode, you'll be more aware of whether movement will be sharp or blurry.
When using program exposure mode, or the action icon (jogger figure), the camera will most often freeze any motion.
If you're photographing movement, such as sports, dance, and waterfalls, you may want to use shutter-priority exposure mode to blur motion.