Before we explored the differences between prokaryotic and eukaryotic cells we should understand what nucleus is. Nucleus commonly exists in the center of a cell and controls the whole coordination and working capacity of it similar to human brain. They also contains the genetic material like DNA and RNA which inherits from one generation to the other. Based on presence and absence of the well structured nucleus prokaryotes and eukaryotes can be differentiate from each other:
Prokaryotic is a greek word which can split in to pro meaning primitive and karyon that means nucleus. So if we combined these two english meanings together then it gives the definition that prokaryotes are the organisms which contains primitive nucleus. That further can understand by the fact that the nucleus which is not in a very well defined shape and does not contain a particular structure. The DNA or RNA (genetic material) of the prokaryotes found spread in the liquid portion of the cells. Whereas, eukaryotes (eu = true and karyon = nucleus) means organisms which contains true nucleus. This explains that eukaryotic organisms contains a well defined and structured nucleus in which genetic material found inside the nucleus and protected by the nucleus covering (nuclear membrane).
Besides prokrayotes are generally made up of only one cell that is why they are normally called unicellular (single celled organisms), and eukaryotes are made up of more then one cell and known as multicellular (made up of multiple cells) organism.
Also, prokaryotes are found missing with the various other cellular organelles like chloroplast, mitochondria, golgi body, endoplasmic reticulum, lysosome including others and these organelles are commonly found in the eukaryotic cells. Only ribosome (70S type) cellular organelle exists in the prokaryotic cell but in eukaryotic cell 80S type ribosome has been found.