| antimony |
a chemical element that has fifty-one protons in each nucleus and forms a brittle bluish white metal crystal, used in hard alloys, electrical components, and medicines. (symbol: Sb) |
| barium |
a chemical element of the alkaline-earth group that has fifty-seven protons in each nucleus and that is usu. found in compounds such as salts. (symbol: Ba) [1/2 definitions] |
| cerium |
a highly reactive chemical element of the rare-earth group that has fifty-eight protons in each nucleus and that occurs naturally only in compounds. (symbol: Ce) |
| cesium |
a highly reactive chemical element of the alkali metal group that has fifty-five protons in each nucleus and that occurs in pure form as a soft, silvery metal melting to a heavy liquid just above room temperature. (symbol: Cs) [1/2 definitions] |
| fiftieth |
indicating rank or position between forty-ninth and fifty-first. [3 definitions] |
| fifty |
(pl.) the period in one's life from age fifty through age fifty-nine. [2/5 definitions] |
| half dollar |
a coin of the United States and Canada worth fifty cents. |
| iodine |
a highly reactive chemical element of the halogen group that has fifty-three protons in each nucleus and occurs naturally in compounds such as salts, and in pure form as a poisonous bluish black crystal. (symbol: I) [1/2 definitions] |
| ionosphere |
layers of the earth's atmosphere located above the stratosphere from about thirty to two hundred and fifty miles above the earth's surface, and composed of rarefied gases that have been ionized by radiation from the sun. |
| lanthanide series |
a series of chemical elements having from fifty-seven to seventy-one protons in each nucleus; rare-earth elements. |
| lanthanum |
a chemical element of the rare-earth group that has fifty-seven protons in each nucleus and that occurs as a soft, highly reactive, solid metal or as a trivalent ion. (symbol: La) |
| magnum |
a wine or spirit bottle holding 1.5 liters, or about fifty ounces. [1/3 definitions] |
| mesosphere |
the earth's atmosphere between the stratosphere and the thermosphere, or from twenty miles to fifty miles above the earth's surface. |
| Miserere |
the fifty-first psalm, or a musical setting for it. [1/2 definitions] |
| Moab Isolation Center |
a special U.S. internment camp located near Moab, Utah, occupied in 1943 by American citizens of Japanese descent who had been deemed to be "trouble-makers" during their previous internment at ordinary camps created for the holding of Japanese-Americans during World War II. The conditions at the Moab Isolation Center were harsher than at other camps. At its peak, there were about fifty people being held there. |
| playing card |
one of a set of usu. fifty-two cards that are divided into four suits of spades, clubs, hearts, and diamonds, and are used in playing various games. |
| praseodymium |
a rare-earth metallic chemical element that has fifty-nine protons in each nucleus and that is usu. found together with neodymium. (symbol: Pr) |
| proof spirit |
an alcoholic beverage, or mixture of alcohol and water, that contains fifty percent alcohol by volume. |
| quinquagenarian |
fifty years old or between the ages of fifty and sixty. [2 definitions] |
| rare-earth metal |
any of the series of chemical elements, all metals, that have from fifty-seven to seventy-one protons per atom; lanthanide series. |
| sidereal day |
a unit of time equal to the time required for one rotation of the earth; twenty-three hours, fifty-six minutes, and 4.1 seconds. |