The word "regionalize" means the act of dividing or organizing something according to regions. It is essentially a process of categorizing things geographically. If you're tired of using the same word repeatedly, here are some synonyms that can be used instead. One word that can be used in place of regionalize is "partition." Other alternatives include "localize," "segment," "zone," or "district." Some other phrases that can be used are "geo-stratify" or "geographically categorize." Having synonyms can prove helpful when you need to vary your writing, and these options listed above can be used interchangeably with "regionalize".