| Aristotle |
a Greek philosopher (384-322 B.C.). |
| arithmetic |
the simplest form of mathematics consisting of the theory and computation of whole numbers, including addition, subtraction, multiplication, division, evolution, and involution. [3 definitions] |
| arithmetician |
one skilled in arithmetic. |
| arithmetic mean |
the sum of a series of quantities divided by the number of quantities; average. |
| arithmetic progression |
a sequence of numbers that results from adding a constant number, such as 4, to each previous number, and thus obtaining a series such as 6, 10, 14, 18, 22, 26. |
| -arium |
a place or device associated with or pertaining to; -orium. |
| Arius |
a Greek theologian and Christian priest in Alexandria (256?-336 A.D.). |
| Arizona |
a southwestern U.S. state between California and New Mexico. (abbr.: AZ) |
| ark |
(sometimes cap.) according to the Old Testament, a large boat built by Noah to preserve life during the Flood. [4 definitions] |
| Arkansas |
a south central U.S. state between Mississippi and Oklahoma. (abbr.: AR) |
| ark of the covenant |
according to the Old Testament, the sacred chest in which the ancient Hebrews carried the two stone tablets inscribed with the Ten Commandments. |
| arm1 |
either of the two upper limbs of the human body, between the shoulders and the wrists. [3 definitions] |
| arm2 |
(usu. pl.) weapons, esp. those that shoot or explode. [7 definitions] |
| armada |
a fleet of armed ships. [2 definitions] |
| armadillo |
a burrowing nocturnal mammal of the southern United States and South America, whose body is armored by jointed, bony plates. |
| Armageddon |
according to the New Testament, the place where the final, decisive conflict between good and evil will be fought. [2 definitions] |
| armament |
weapons and supplies used to equip a military unit such as a tank, warship, airplane, or the like. [4 definitions] |
| 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. [4 definitions] |
| armband |
a cloth band worn around the upper arm as a badge of rank, membership, or the like, or as a symbol, as of mourning. |
| armchair |
a chair having supports at the sides for resting one's arms. [2 definitions] |
| armed |
holding or bearing weapons. [4 definitions] |