The Universe is defined as everything that physically exists: the entirety of space and time, all forms of matter, energy and momentum, and the physical laws and constants that govern them. However, the term "universe" may be used in slightly different contextual senses, denoting such concepts as the cosmos, the world or Nature.

 

Astronomical observations indicate that the universe is 13.73 ± 0.12 billion years old and at least 93 billion light years across. The theoretical event that started the universe is called the Big Bang. At... Read more »

Music is an art form in which the medium is sound organized in time. Common elements of music are pitch (which governs melody and harmony), rhythm (and its associated concepts tempo, meter, and articulation), dynamics, and the sonic qualities of timbre and texture. The word derives from Greek μουσική (mousike), "(art) of the Muses".

 

Greek philosophers and ancient Indians defined music as tones ordered horizontally as melodies and vertically as harmonies. Music theory, within this realm, is studied with the presupposition that music is orderly and often ple... Read more »

Murder is the unlawful killing of a human person with malice aforethought, as defined in Common Law countries. Murder is generally distinguished from other forms of homicide by the elements of malice aforethought and the lack of lawful justification. All jurisdictions, ancient and modern, consider it a most serious crime and therefore impose severe penalty on its commission.

 

Common law murder is defined as the unlawful killing of a human person with malice aforethought if the defendant acts with any of the following states of... Read more »

A suicide attack is an attack upon a military or civilian target, in which an attacker intends to kill others and/or cause great damage, knowing that he or she will either certainly or most likely die in the process (see suicide). The means of attack have included vehicles filled with explosives, passenger planes carrying large amounts of fuel, and individuals wearing vests filled with explosives. Synonyms include suicide-homicide bombing, martyrdom operations, predatory martyrdom. Strictly speaking, an attack may not be considered a suicide attack if the att... Read more »

Love represents a range of human emotions and experiences related to the senses of affection and sexual attraction.The word love can refer to a variety of different feelings, states, and attitudes, ranging from generic pleasure to intense interpersonal attraction. This diversity of meanings, combined with the complexity of the feelings involved, makes love unusually difficult to consistently define, even compared to other emotional states.

As an abstract concept love usually refers to a strong, ineffable feeling towards another person. Even this limited conception of love, however, encompasses a wealth of different f... Read more »

A language is a dynamic set of visual, auditory, or tactile symbols of communication and the elements used to manipulate them. Language can also refer to the use of such systems as a general phenomenon. Language is considered to be an exclusively human mode of communication; although animals make use of quite sophisticated communicative systems, none of these are known to make use of all of the properties that linguists use to define language.

 

A set of agreed-upon symbols is only one feature... Read more »

A planet, as defined by the International Astronomical Union (IAU), is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.

 

The term planet is an ancient one having ties to history, science, myth, and religion. The planets were originally seen as a divine presence; as emissaries of the gods. Even today, many people continue to believe the movement of t... Read more »

Technology is a broad concept that deals with a species' usage and knowledge of tools and crafts, and how it affects a species' ability to control and adapt to its environment. In human society, it is a consequence of science and engineering, although several technological advances predate the two concepts. Technology is a term with origins in the Greek "technologia", "τεχνολογία" — "techne", "τέχνη" ("craft") and "logia", "λογί... Read more »

A world war is a war affecting the majority of the world's most powerful and populous nations. World wars have spanned several continents, and lasted for years. History has shown that as a world war progresses, involved nations devote more and more of their resources to the conflict, resulting in ever-escalating destruction. World wars have resulted in unparalleled devastation. Almost every nation involved has suffered deeply, and the loss of life can only be estimated.

 

Origins of the term

The term "World War" was coined speculatively in the early 20th century, some years before the... Read more »