The definition of septet is very simple. It merely means the number 7. This means that anything in a group of seven can be considered to be a section of a septet. Some of the most famous septets would be Snow White and the Seven Dwarfs. There were 7 of them so that would make them a septet. Other famous sets of seven, or septets, would be the deadly sins. It is said that there are 7 deadly sins.
. A septet is a common term used in mathematics. A sextet would be a group of six and an octet is a group of 8. A septet is actually a noun if you are considering the part of speech that it can be. There was a woman who gave birth to 7 children and they have always been known as the septuplets. The woman who had 8 children had octuplets. A septet actually means a group of 7 and not really the number 7. The number seven has been known to be considered the luckiest number of all of them. In casinos you will see slot machines where you need to get three sevens.