Root יעד (originally ועד) has a basic meaning of "to do something for a purpose" and another one "to meet". Accordingly are meanings of נועד and מיועד. Looking at the dictionary entries mentioned above, we see that:
> נועד is either "to be designed for, to be intended for; to be designated, to be destined" or "to meet, to get together".
> מיועד is "designate; appointed"
In modern Hebrew (assuming this is what the question is about), נועד is used first of all for the meaning of "to meet" but also for "to be designated for" and its alikes. מיועד is used for "to be designated for" and no for "to meet". So there's an overlap in these two meanings, and yet there's typical preference in usage.