The English word world continues Old English�weorold (-uld), weorld, worold (-uld, -eld), a compound of wer "man" and eld "age", thus translating to "Age of Man". The Old English continues a Common Germanic�*wira-alđiz, also reflected in Old Saxon werold, Old High German weralt, Old Frisian warld and Old Norse verǫld (whence the Icelandic veröld).

The history of the world is the recorded memory of the experience, around the world, of Homo sapiens. Ancient human history begins with the invention, independently at several sites on Earth, of writing, which created the infrastructure for lasting, accurately transmitted memories and thus for the diffusion and growth of knowledge. Nevertheless, an appreciation of the roots of civilization requires at least cursory consideration to humanity's prehistory. Human history is marked both by a gradual accretion of discoveries and inventions, as well as by quantum leaps—paradigm shifts, revolutions—that comprise epochs in the material and spiritual evolution of humankind.

The relative security and increased productivity provided by farming allowed these communities to expand. Surplus food made possible an increasing division of labor, the rise of a leisured upper class, and the development of cities and thus of civilization. The growing complexity of human societies necessitated systems of accounting; and from this evolved, beginning in the Bronze Age, writing. The independent invention of writing at several sites on Earth allows a number of regions to claim to be cradles of civilization.

In Europe, the fall of the Western Roman Empire (476 CE) is commonly taken as signaling the end of antiquity and the beginning of the Middle Ages. A thousand years later, in the mid-15th century, Johannes Gutenberg's invention of modern printing, employing movable type, revolutionized communication, helping end the Middle Ages and usher in modern times, the European Renaissance and the Scientific Revolution.

The world population is the total number of living humans on Earth at a given time. As of 19 March 2010, the Earth's population is estimated by the United States Census Bureau to be 6,809,300,000. The world population has been growing continuously since the end of the Black Death around 1400. The fastest rates of world population growth (above 1.8%) were seen briefly during the 1950s then for a longer period during the 1960s and 1970s (see graph). According to population projections, world population will continue to grow until at least 2050. The 2008 rate of growth has almost halved since its peak of 2.2% per year, which was reached in 1963. World births have levelled off at about 134 million per year, since their peak at 163 million in the late 1990s, and are expected to remain constant. However, deaths are only around 57 million per year, and are expected to increase to 90 million by the year 2050. Because births outnumber deaths, the world's population is expected to reach 9 billion in 2040.

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