What is "hendecagram"

In geometry, a hendecagram (also endecagram or endekagram) is a star polygon that has eleven vertices.

The name hendecagram combines a Greek numeral prefix, hendeca-, with the Greek suffix -gram. The hendeca- prefix derives from Greek ἕνδεκα (ἕν + δέκα, one + ten) meaning " eleven". The -gram suffix derives from γραμμῆς (grammēs) meaning a line.