"Fons et origo" is a Latin phrase that means "source and origin" in English. There are several synonyms that can be used to convey the same meaning, such as "genesis," "beginning," "foundation," "root," "originating point," "starting point," "inception," and "commencement." These synonyms can be used in various contexts to describe the beginning or the source of something. For instance, "genesis" can be used to describe the creation or origin of something, while "foundation" can be used to describe the base or underlying support of something. Ultimately, these synonyms can help to add depth and variety to language when discussing the origin or source of various concepts or ideas.