The prefix "hepta-" comes from the Greek word "heptá" meaning seven. It is commonly used in scientific terminology to denote a seven-fold number or quantity. Synonyms for "hepta-" include "sept-", "septi-", and "septem-", all of which also signify the number seven. Another possible synonym is "septuple", which refers to a group or set of seven. Additionally, the word "heptagon" refers to a seven-sided polygon and could be considered a synonym for "hepta-" in terms of shape or geometry. Overall, these synonyms provide alternative ways to express the concept of seven and can be used in various scientific and mathematical contexts.