$(1)$ Definition / Explanation: Karyokinesis
$(2)$ Definition / Explanation: Cytokinesis

(N/A) $(1)$ Karyokinesis is the process of division of the nucleus during cell division,which occurs in both mitosis and meiosis.
$(2)$ Cytokinesis is the process of division of the cytoplasm,which marks the completion of cell division. In animal cells,cytoplasmic division occurs by the formation of a cleavage furrow from the periphery to the center. In plant cells,it occurs by the formation of a cell plate starting from the center and extending towards the periphery,eventually leading to the formation of the nuclear membrane and two daughter cells.