To isolate means to contain or withhold within a certain boundary. Nothing goes in, nothing goes out. Whatever is being isolated is protected from most means of harm - Yes, I said "most", because isolation doesn't always have its benefits. Believe me, I know.
We'll isolate this hot liquid in the thermos, it won't spill and it won't lose heat!
An area within the cervix. When the vagina is penetrated and the individual doing the penetrated has a penis of larger stature, you may pass into this area. This hurts the female more than childbirth.
The situation when an iPhone- or iPad-addicted person is separated from their device for any length of time. It leads to feelings of fear and awe at the wide world around them they never bother with the rest of the time.
Dave: "Damn it! I've left my iPhone at home! Now I'm totally iSolated!"