There is slight difference between distilled and de-ionized water,
distilled water will be free from positive, negative ions along with bacteria and fungus etc. You can also drink it, use it in car batteries or for any purpose where your aim is to use most purified form of water.
De-ionized water undergoes through some process which gets rid of positive and negative ions from water but bacteria and fungus will remain there. It may not be safe for drinking but perfect for batteries, radiator and other purposes where you donāt want salts in water.