Rayovac High Energy Alkaline, 9V Batteries, 4 Count

4 (four) is a number, numeral and digit. It is the natural number following 3 and preceding 5. It is a square number, the smallest semiprime and composite number, and is considered unlucky in many East Asian cultures.

9V or 9-V may refer to:

• Nine-volt battery
• Killed by 9V Batteries, an Austrian indie rock band
• PG-9V, a model of the SPG-9 gun
• 9V Avior Airlines - IATA code
• Singapore - aircraft registration code

Count (feminine: countess) is a historical title of nobility in certain European countries, varying in relative status, generally of middling rank in the hierarchy of nobility. Especially in earlier medieval periods the term often implied not only a certain status, but also that the count had specific responsibilities or offices. The etymologically related English term "county" denoted the territories associated with some countships, but not all.

Although the term count was not generally used in England, after the 1066 conquest by the Normans, various European terms for count eventually became the normal translations used for the English title of earl, and the wives of earls are still referred to as countesses.

In physics, energy (from Ancient Greek ἐνέργεια (enérgeia) 'activity') is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light. Energy is a conserved quantity—the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The unit of measurement for energy in the International System of Units (SI) is the joule (J).

Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object (for instance due to its position in a field), the elastic energy stored in a solid object, chemical energy associated with chemical reactions, the radiant energy carried by electromagnetic radiation, and the internal energy contained within a thermodynamic system. All living organisms constantly take in and release energy.

Due to mass–energy equivalence, any object that has mass when stationary (called rest mass) also has an equivalent amount of energy whose form is called rest energy, and any additional energy (of any form) acquired by the object above that rest energy will increase the object's total mass just as it increases its total energy.

Human civilization requires energy to function, which it gets from energy resources such as fossil fuels, nuclear fuel, or renewable energy. The Earth's climate and ecosystems processes are driven by the energy the planet receives from the Sun (although a small amount is also contributed by geothermal energy).