Can you name this schematic symbol?
This is a current source symbol.

It provides a constant current (whose value should be written next to the symbol), whatever the voltage across it. And basically, it's the opposite of a constant voltage source (ideal power supply).

Its meaning is not different from the usual symbol with a single circle.

Here are different symbols for current source:

Source: https://commons.wikimedia.org/wiki/File:Ideal_current_source_symbols.svg


They all mean the same. 


a is the usual US symbol.
b is a variant of a.
c is the DIN40700 symbol (german).
d is the usual european symbol.
e never saw that one before today, actually.


Your specific symbol is actually a mix of a and d. Half-US, half-european. A "melting pot" symbol, somehow.