heptode
/ˈhɛptəʊd/Definitions
1. noun
In geometry, a heptode is a heptagon with the additional property that any five of its vertices form a cyclic pentagon.
“The mathematician studied the properties of heptodes in her research paper.”
2. noun
A heptode can also refer to a musical instrument with seven strings.
“The musician played a beautiful melody on her heptode during the concert.”