Prokaryotes and Eukaryotes
Pro means "before", and karyose means "kernel", as a kernel of grain. Early scientists referred to a cell nucleus as a karyose since it looked like a kernel in the cell. Prokaryotic therefore means "before a nucleus"
Eu means "true" and karyose means "kernel", eukaryotic therefore means "possessing a true nucleus."
So boiling it down:
Pro = no
Prokaryotes, no nucleus
Eu = Do
Eukaryotes, you do have a nucleus