The name of the heroine in Arina Tanemura's one-chapter bonus manga 'Gin-yu Mieka'. Her father is a composer who named one of his pieces after her: Kanon.
This is also a Greek noun. Greek - Kappa, Alpha, Nu, Omicron, Nu, means "standard rule or measure. Also used to refer to what exactly is contained in holy scriptures, e.g. "the Canon of the Church", though spelled with a "C".