The term "first born" can be replaced by numerous synonyms depending on the context. Some of the common synonyms include "eldest," "firstborn child," "first offspring," "initial child," and "original descendant." These terms all mean the first child born into a family, and can be used interchangeably. However, in some cultures, the term "primogeniture" is used, which refers to the custom of the firstborn inheriting the family's entire estate. Moreover, the word "pioneer" is also a synonym for the term "first born" when its meaning is extended beyond a familial context. In this case, a pioneer is someone who is the first person to discover or do something, paving the way for others.