Stripboards (sometimes called veroboards) are typically used for prototyping electronic circuits. They have little holes, evenly spaced at 0.1 inches (yes, even in Europe - electronic components usually have their pins 1/10″ (0.254 mm) apart.
The image shows the soldering side - usually the back or bottom side. You stick the components in from the other side and solder on this side, and then cut off the pins so they don’t stick out too far.

See also: Yoshi’s DIY stripboard cutter