These terms are generally referencing most of the religiously founded countries based on Abrahamic practices (Judaism, Christianity, and Islam), rather than simply an “East/West” divide based on the Prime Meridian and International Date Line.
This is not a pejorative term, but instead is used to illustrate a split in the types of understanding between the Oriental and Occidental worlds. There are major overlaps in the “middle east” regions, specifically along the route classically referred to as the Silk Road, where many different practices would have had discourse.
For the most part, “Western World” or “Westerner” would include North and South America, Australia, New Zealand, as well as the United Kingdom and most of the European Union and Slavic countries. The “Eastern World” would include most of the remainder of the world.