ˈdīəsə̇s noun
( plural die·ses -əˌsēz)
Etymology: Latin, from Greek, from diienai, to drive through, let go through (from dia- + hienai to let go, send, throw) + -sis — more at jet
1.
a. in ancient Greek music : limma
b. : enharmonic diesis
c. : sharp IV c(1), c(2)
2. : double dagger — compare reference mark