| aquifer |
a bed of rock, sand, or gravel that can hold great quantities of water and supplies it to wells and springs. |
| armature |
a coil-wrapped iron core that rotates in a magnetic field to induce electrical current in a generator, or that produces motion in an electrical motor when current is passed through it. [1/4 definitions] |
| armpit |
the hollow formed beneath the arm where it joins the body. |
| arm wrestling |
a contest in which each of two opponents places either the right or the left elbow on a table with the forearm vertical, clasps the opponent's hand, and tries to force the opponent's hand back until it touches the table; Indian wrestling. |
| Articles of Confederation |
a document created in 1781 that served as a set of guidelines for governing the newly formed United States of America. The Articles of Confederation created a "firm league of friendship" among the thirteen original states and maintained the majority of power in states' hands. It was replaced by the U.S. Constitution in 1789. |
| as if |
how it would be if. |
| assimilate |
in phonetics, to modify (a sound) to make it resemble a linguistically adjacent sound. [1/8 definitions] |
| assize |
a judicial inquest, the legal order on which it is convened, or the verdict issuing from it. [1/4 definitions] |
| atavism |
the reappearance of a biological characteristic in an organism after it has not appeared for several generations, or an organism displaying such a characteristic. [1/2 definitions] |
| Augean |
of or suggesting Augeas, a king in Greek mythology, or his stables, which had not been cleaned for thirty years until Hercules changed the course of a river so that it swept through them. [1/2 definitions] |
| autoradiograph |
a picture produced on a film by placing it in contact with a radioactive substance. |
| axil |
the upper angle between a leaf, flower, twig, or the like, and the stem or branch from which it grows. |
| back-order |
to submit an order for (something) to be filled at a later time, as when (it) is available. |
| backspin |
a reverse spin put on a ball, such as a billiard or tennis ball, that causes it to stop suddenly or move in a backward direction. |
| backswing |
in sports, the first part of the swing of a bat, club, racket, or the like, in which it is swung toward the player's back in preparation for the forward swing. |
| baker |
a person who bakes, esp. one who is highly skilled at baking or does it professionally. [1/2 definitions] |
| ballast |
heavy material placed in the hold of a boat or ship to make it more stable. [2/4 definitions] |
| ball cock |
a device used to regulate the supply of water in a tank or toilet, consisting of a lever connected to a floating ball that shuts a valve when raised and opens it when lowered. |
| ball lightning |
a rare form of lightning manifested in the form of a glowing reddish ball, approximately six inches to a foot in diameter, that moves rapidly along the ground or in the air until it disintegrates. |
| balloon |
such a bag with a basket or gondola connected to it, used to transport passengers or scientific equipment. [1/8 definitions] |
| balustrade |
a rail and the set of balusters, or posts, that support it. |