Ordinal Follower list
Use the Ordinal Followers dialog to view or edit a list of standard ordinal followers for the current language. Ordinal followers are used during segmentation. This aspect of segmentation is not relevant for all languages, but it is particularly useful for the German language.
Considering the date expressed in German as 15. Oktober if Oktober were not in the list of ordinal followers, "15." would denote the end of a segment and Oktober would start another segment.
When Trados Studio encounters an ordinal follower from the Ordinal Followers list in the source language, it knows that the full stop that precedes it is not the end of a segment. Thus, the segmentation of the source text is done correctly.