In science, neutral means one of three things: something that is gray and without hue or zero chroma; something that does not have a charge and is not magnetized; or something that does not exhibit acid or alkaline qualities. Neutral has many meanings outside of science as well and can mean belong to a neutral state or party and not taking part or giving assistance during a dispute or war between others.
In physics, an electrically neutral atom contains equal numbers of both protons and electrons. If the atom has an unequal number of protons and electrons then the atom is considered electrically charged. In this case, it is also called an ion instead of an atom. Neutral is also often referred to as uncharged.
In chemistry, substances are determined to be alkalis, also referred to as base, neutral or acidic. All neutral substances have common characteristics and properties. They tend to be harmless and are not dangerous to humans or animals. A neutral paper will also not affect a litmus paper and the universal indicator will stay green when tested with a neutral substance. Common examples of neutral substances include the sugar solution C6H12O6 (aqueous), the sodium chloride solution NaCl (aqueous; also known as common salt) and plain water.