But in 1975 UK government officially switched to short scale system and today meaning of this word is 1e9. And there is no milliard word in English any more accept in historical books...

As state:

https://en.wikipedia.org/wiki/Names_of_large_numbers

Wikipedia article on large number names.

there are two common systems of naming of large numbers - short scale and long scale.

Short scale is used in US and also in use in former USSR countries where I live. And as I mentioned above UK switched to short scale, making this system international.

According to:

https://en.wikipedia.org/wiki/Long_and_short_scales

Wikipedia article on history of large number names.

firstly long scale naming schema was used. This schema keeps in use in French/Spanish speaking countries.

Each step beyond million is million in long scale system, while is short scale system each step beyond million is thousand: