in my view an ideal voltage souce means which is having
constant voltage irrespect of the current and having zero
internal resistance which is in series with the voltage
source

a voltage source witch in zero internal resistance is called ideal voltage source.
so any change in load resistance should not change in supply voltage

ideal voltage source is a circuit element where the voltage
across it is independent of current through it (i.e)
voltage remains constant and also the internal resistance
is zero

IT HAS A ZERO SERIES IMPEDANCE . IT IS ABLE TO PROVIDE A SAME VOLTAGE ACROSS ALL THE LOADS . IT HAS NO ANY LOSSES OR NO ANY POWER DISSIPATION .........