Sarcophagus: A container or coffin, usually made of stone, used to hold the mummy of an ancient Egyptian.

Scribes: Ancient Egyptians trained to read and write hieroglyphics.

Serpent Mound: A snake-shaped site in south-central Ohio built by Native Americans of the Fort Ancient culture between A.D. 900 and 1600.

Sherd: Or shard. A broken fragment of pottery.

Site: An area designated for archaeological exploration by excavation and/or survey.

Sphinx: A figure made up of two different kinds of animals, or half man-half animal. Some of the animals found in sphinxes include rams, lions, crocodiles, and hawks. The best-known example is the Great Sphinx, located in Giza, Egypt, which has the body of lion and the head of a man.

Stone Age: The earliest technological period in human culture when tools were made of stone, wood, bone, or antlers. Metal was unknown. The dates of the Stone Age vary considerably from one region to another, and some communities were still living a Stone Age life until very recent times. It is subdivided into the Paleolithic, Mesolithic, and Neolithic. The Stone Age was followed by the Bronze Age and then the Iron Age.

Stonehenge: Near the town of Avebury in Wiltshire, England. Stonehenge is perhaps the finest of the British megalithic monuments. It stands in the center of Salisbury Plain, surrounded by a complex of cemeteries and ritual sites. Stonehenge is believed to date to about 2780 B.C., near the end of the Neolithic period. The function of the monument is thought to have been spiritual, but the arrangement of the megaliths also suggest possible astronomical uses, such as a calendar.

Stratification: Layers of deposits that provide archaeologists with one of the major tools or clues for interpreting archaeological sites (stratigraphy). Over time, debris and soil accumulate in layers. Color, texture, and contents may change with each layer. Archaeologists try to explain how each layer was added--if it occurred naturally, deliberately (garbage), or from the collapse of structures--and they record it in detailed drawings so others can follow.

Stratigraphy: Refers to the interpretation of the layers in archaeological deposits. By examining and analyzing the layers (strata) and the artifacts in them, archaeologists can learn how past people lived and what kinds of things they did. Usually, the artifacts found on top are the youngest (most recent), while those on the bottom are the oldest. If the stratigraphy gets mixed up (for example, if someone digs a hole down into it) then interpretation becomes much more difficult, and sometimes impossible. If this happens, artifacts are no longer in context.

Stratum: (The plural is strata.) A single depositional layer, usually seen as part of more complex stratigraphy consisting of several strata.

Sumer: A region in the southern part of ancient Mesopotamia. The Sumerians appeared around 5000 B.C.; the civilization was made up of independent walled city-states, and declined around 2350 B.C. with the rise of the Akkadian Empire. Sumerian culture was revived at the very end of the 3rd milenium BC. during the 'Third Dynasty of Ur' after which time the Old Babylonian culture ruled Mesopotamia. However, the Sumerian writing system (cuneiform) was used throughout the Ancient Near East for another 2,000 years.

Superposition: This describes how layers are usually laid down according to their age: the oldest layer is found on the bottom, and the most recent layer is on top. So, if a layer is on top of another layer, it is probably more recent.

Survey: To examine the land to locate and record artifacts and sites.

Tape Measure: A tape measure is used to lay out a grid over an archaeological site, to measure each unit to make sure it is square, to measure the depth of each level, and to measure the distance of each feature from the corner of the unit. This tool is essential to archaeologists.

Terra Cotta Soldiers: The more than 7,000 terra-cotta figures that were found in the tomb of the Emperor Qin Shihuangdi, China's first emperor (221­206 B.C.). The tomb is located central China's, Xi'an province.

Theory of Evolution: Charles Darwin's theory developed in A.D. 1859, in his book Origin of Species. Darwin theorized that humans evolved from a lower order of animals, such as primates.

Thermoluminescence: [Is it right for me to call this a dating method?] A method of dating that measures the energy given off from the breakdown of radioactive elements. This energy is trapped in pottery and given off as light. Older objects give off more light.

Thomas Jefferson: America's third president (1801 to 1809). Jefferson was fascinated by archaeology, especially the burial mounds that had been discovered along the eastern coast of the United States. Jefferson conducted his own excavations on some of these burial mounds and developed many of the techniques still used in modern scientific archaeological excavation.

Traditions: Customs or beliefs passed down from adults to children.

Traits: Any element of human culture, material objects, or human practices.

Transit: A scientific instrument used on excavations to measure horizontal and vertical angles and horizontal distances in order to find out changes in soil level during excavation and the distances between different points of excavation.

Tree Ring Dating: See dendochronology.

Triassic Period: Between 248 and 206 million years ago. Period characterized by the appearance of the first dinosaurs and mammals on earth.

Trowel: A tool used by archaeologists to dig in the ground. A trowel is very useful because it allows them to dig in a sideways, scraping fashion. It's important to clear off one level in a unit before digging down to the next level. An archaeologist's trowel is straight-edged, not curved like a shovel or garden trowel.

Tuff: Deposits of volcanic ash that have formed a crust-like layer over the underlying land.

Tundra: Almost treeless plains next to the polar ice. All but the top few inches of soil are permanently frozen.

Tutankhamun: The famous boy pharaoh who began to rule Egypt when he was only nine years old (he ruled from about 1333 to 1323 B.C., during the New Kingdom). His undisturbed tomb was found by archaeologist Howard Carter in 1922.

Underwater Archaeology: The process of excavating archaeological material covered by fresh or seawater.

Unit: Archaeologists lay out a grid over a site to divide it into units, and then they figure out which units will be dug. Units vary in size. Archaeologists dig one unit at a time. Keeping track of specific measurements between artifacts and features gives archaeologists the ability to draw an overall map looking down on the site (called a floor plan), to get the bigger picture of the site.

Urn: A pottery vessel, usually rather large, deep, and without handles. Urns were (and still are) most often used for holding the ashes and bones of the dead and were sometimes buried.

Vandalism: The malicious and intentional destruction or defacing of property. The word derives from a tribe of Germanic peoples, the Vandals, who invaded the Roman Empire in the 4th and 5th centuries A.D. They eventually settled in North Africa, where they remained until the 530s, when they were conquered by Emperor Justinian of the Byzantine Empire.

Vikings: A culture originating in Scandinavia (now Norway, Denmark and Sweden) around the mid-8th century A.D. The Vikings were fierce conquerors, brave explorers, and skilled craftspeople; they invaded and settled countries throughout Western Europe. They were the first Europeans to discover America (in about A.D. 1000), almost 500 years before Columbus.

Wonders of the World: A list made by Greek writers in the second century B.C.: (1) the Pyramids at Giza, (2) the Hanging Gardens of Babylon, (3) the Statue of Zeus at Olympia, (4) the Temple of Diana at Ephesus, (5) the Mausoleum at Halicarnassus, (6) the Colossus of Rhodes, and (7) the Pharos of Alexandria lighthouse. Only the Pyramids at Giza survive.

Ziggurat: A type of step-pyramid temple first built by the Sumerians 5,000 years ago in southern Mesopotamia, made of sun-dried mud bricks. The peoples of Mesopotamia continued building ziggurats for thousands of years.