Septenary is a term that describes anything related to the number seven. However, there are several other words that you can use to express the same concept. One of them is heptadic, which is derived from the Greek word "hepta," meaning seven. Another synonym is sevenfold, which indicates something that is made up of seven parts or aspects. You can also use the word septuplicate to refer to something that has been replicated seven times. Additionally, the term sevensome refers to a group of seven people or things, while septennial is used to describe an event or occurrence that takes place every seven years.