What's correct name of this circuit element — switch or toggle?
The name of the symbol is "switch". See BBC Bitesize Electrical Circuit Symbols.
A switch is a circuit element which is intended to connect or disconnect an electric current, so what you show is a switch. In UK usage the word 'switch' is often combined with another word to show what sort of physical switch is meant, so a toggle switch is operated by a lever (as stated by Andrew Leach). In my fifty-plus years of electrical engineering I have not come across 'toggle' on its own in this context.
There are also rocker switches, push switches, tilt switches and many others.