What is shutterspeed in photography?

In your camera there is a small curtain that rolls over the sensor and lets light shine on the sensor in the photo camera to take a picture. The brightness of the image depends on the movement of the shutter. If the shutter moves slower this means that more light will go inside and the image will be brighter. 

The unit to measure the duration that shutter allows light to shine on the image sensor is called shutter speed. Shutter speed is measured in fractions of a second, shutter speed of 1/4 means that the movement of shutter is slower than the shutter speed of 1/250, means the image with a shutter speed of 1/4 will be brighter than the shutter speed of 1/250, in the same situation, as it will let the light shine for a longer period of time.

Shutter speed also controls how blurry the photo is. At the shutter speed of 1/4 the photo will be more blur as the sensor will take the picture for a longer time if you compare it to a shutter speed of 1/250.