What are the East and West terminus of the TransSiberianExpress?

The Trans-Siberian Railway is the term for routes traversing Siberia.

The Trans-Siberian crosses the breadth of Russia, from Moscow in the west, to Vladivostok in the east.

According to the following source:

Routes not trains, note; there's no such thing as the "Trans-Siberian Express".

https://en.wikipedia.org/wiki/Wikivoyage:Trans-Siberian_Railway

The Trans-Siberian Railway is considered to be the World's longest railway line. The length is some 9,289 kilometres (5,772 miles).
https://en.wikipedia.org/wiki/Trans-Siberian_Railway

The Western terminus is Yaroslavsky railway station, one of nine major railway stations in Moscow.

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

The Eastern terminus is Vladivostok railway station.

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