The phrase "horn amalthea" refers to the horn of plenty in Greek mythology, which was said to provide an endless supply of food and drink. However, there are various synonyms and alternative terms that can be used to describe this mythical object. Some of these include "cornucopia," "hollow horn," "goat's horn," and "horn of abundance." These synonyms evoke similar images of a vessel overflowing with riches and abundance, and can be used interchangeably with "horn amalthea" to add variety and depth to descriptions of mythical objects or events in stories and literature.