Typical wall voltage in most of Europe, many places in Asia, and almost all of Africa is between 220 and 240 Volts, alternating current, 50 Hz. 220 is also used for heavy electrical loads in countries that standardize on 110.
When an electrician says "two twenty", this is what he is referring to.
A 220 Volt electric shock is very powerful and can easily knock you across the room, but this depends on a number of factors including: your body's natural resistance, the shoes you are wearing, how wet your skin is, whether or not you are touching something conductive, and many other things. If conditions are wrong, it wouldn't be very difficult for 220 to kill you.