aperture

Aperture is nothing but the hole in the lens through which light travels. It is denoted by f number on the camera. f-number can be adjusted based on your preference.

For example - Canon G7 X mark II has aperture as "f/1.8-f/2.8". Low f number means larger the hole and more light and vice versa. So if you want brighter photos, keep f number very low. Aperture is useful in creating bokeh effect also called as depth of field. If you want blurry background, you can go for low f number setting. If you want everything in focus, you can go for high f number setting.