Hint: A nucleus is the positively charged core of an atom, made up of protons and neutrons, as described in chemistry. The "atomic nucleus" is also a term for it. The word "nucleus" is derived from the Latin word nucleus, which is a variant of nux, which means nut or kernel. Michael Faraday invented the word in $1844$ to describe an atom's nucleus.
Complete answer: Chemical species that donate or accept electrons to form a new chemical bond are known as electrophiles and nucleophiles. A nucleophile is a chemical species that gives an electron pair to form a chemical bond in response to a stimulus. An electrophile is a molecule, ion, or atom that is deficient in electrons in some way. A nucleophile is a reagent that contains a single electron pair atom. Since a nucleophile has a lot of electrons, it searches for places where there aren't enough, which is why nucleus means "loving nucleus". According to Lewis' concept of acids and bases, nucleophiles behave as Lewis bases. The phrase nucleophile is made up of two words: "nucleo" which comes from the nucleus, and "phile", which means "to love". They have a lot of electrons, but they like nuclei. They are either negatively or neutrally charged. They give electrons away. The density influences electron movement. They move from a low-density to a high-density setting. They are subjected to nucleophilic addition and substitution reactions. Lewis-base is another name for a nucleophile. Nucleophiles are nucleus-loving.
Note: Ammonia is a better nucleophile than water because nitrogen is less electronegative than oxygen. This suggests that the nitrogen-bound lone pair of ammonia is more loosely contained than the oxygen-bound solitary water pairs.